cregit-Linux how code gets into the kernel

Release 4.16 fs/binfmt_flat.c

Directory: fs
// SPDX-License-Identifier: GPL-2.0
/****************************************************************************/
/*
 *  linux/fs/binfmt_flat.c
 *
 *      Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com>
 *      Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
 *      Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com>
 *      Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com>
 *  based heavily on:
 *
 *  linux/fs/binfmt_aout.c:
 *      Copyright (C) 1991, 1992, 1996  Linus Torvalds
 *  linux/fs/binfmt_flat.c for 2.0 kernel
 *          Copyright (C) 1998  Kenneth Albanowski <kjahds@kjahds.com>
 *      JAN/99 -- coded full program relocation (gerg@snapgear.com)
 */


#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/slab.h>
#include <linux/binfmts.h>
#include <linux/personality.h>
#include <linux/init.h>
#include <linux/flat.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>

#include <asm/byteorder.h>
#include <asm/unaligned.h>
#include <asm/cacheflush.h>
#include <asm/page.h>

/****************************************************************************/

/*
 * User data (data section and bss) needs to be aligned.
 * We pick 0x20 here because it is the max value elf2flt has always
 * used in producing FLAT files, and because it seems to be large
 * enough to make all the gcc alignment related tests happy.
 */

#define FLAT_DATA_ALIGN	(0x20)

/*
 * User data (stack) also needs to be aligned.
 * Here we can be a bit looser than the data sections since this
 * needs to only meet arch ABI requirements.
 */

#define FLAT_STACK_ALIGN	max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN)


#define RELOC_FAILED 0xff00ff01		
/* Relocation incorrect somewhere */

#define UNLOADED_LIB 0x7ff000ff		
/* Placeholder for unused library */


struct lib_info {
	
struct {
		
unsigned long start_code;		/* Start of text segment */
		
unsigned long start_data;		/* Start of data segment */
		
unsigned long start_brk;		/* End of data segment */
		
unsigned long text_len;			/* Length of text segment */
		
unsigned long entry;			/* Start address for this module */
		
unsigned long build_date;		/* When this one was compiled */
		
bool loaded;				/* Has this library been loaded? */
	
} lib_list[MAX_SHARED_LIBS];
};

#ifdef CONFIG_BINFMT_SHARED_FLAT
static int load_flat_shared_library(int id, struct lib_info *p);
#endif

static int load_flat_binary(struct linux_binprm *);
static int flat_core_dump(struct coredump_params *cprm);


static struct linux_binfmt flat_format = {
	.module		= THIS_MODULE,
	.load_binary	= load_flat_binary,
	.core_dump	= flat_core_dump,
	.min_coredump	= PAGE_SIZE
};

/****************************************************************************/
/*
 * Routine writes a core dump image in the current directory.
 * Currently only a stub-function.
 */


static int flat_core_dump(struct coredump_params *cprm) { pr_warn("Process %s:%d received signr %d and should have core dumped\n", current->comm, current->pid, cprm->siginfo->si_signo); return 1; }

Contributors

PersonTokensPropCommitsCommitProp
Greg Ungerer2575.76%125.00%
Masami Hiramatsu412.12%125.00%
Denys Vlasenko39.09%125.00%
Nico Pitre13.03%125.00%
Total33100.00%4100.00%

/****************************************************************************/ /* * create_flat_tables() parses the env- and arg-strings in new user * memory and creates the pointer tables from them, and puts their * addresses on the "stack", recording the new stack pointer value. */
static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start) { char __user *p; unsigned long __user *sp; long i, len; p = (char __user *)arg_start; sp = (unsigned long __user *)current->mm->start_stack; sp -= bprm->envc + 1; sp -= bprm->argc + 1; sp -= flat_argvp_envp_on_stack() ? 2 : 0; sp -= 1; /* &argc */ current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN; sp = (unsigned long __user *)current->mm->start_stack; __put_user(bprm->argc, sp++); if (flat_argvp_envp_on_stack()) { unsigned long argv, envp; argv = (unsigned long)(sp + 2); envp = (unsigned long)(sp + 2 + bprm->argc + 1); __put_user(argv, sp++); __put_user(envp, sp++); } current->mm->arg_start = (unsigned long)p; for (i = bprm->argc; i > 0; i--) { __put_user((unsigned long)p, sp++); len = strnlen_user(p, MAX_ARG_STRLEN); if (!len || len > MAX_ARG_STRLEN) return -EINVAL; p += len; } __put_user(0, sp++); current->mm->arg_end = (unsigned long)p; current->mm->env_start = (unsigned long) p; for (i = bprm->envc; i > 0; i--) { __put_user((unsigned long)p, sp++); len = strnlen_user(p, MAX_ARG_STRLEN); if (!len || len > MAX_ARG_STRLEN) return -EINVAL; p += len; } __put_user(0, sp++); current->mm->env_end = (unsigned long)p; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Nico Pitre17949.86%116.67%
Alan Cox14640.67%116.67%
Oskar Schirmer267.24%116.67%
Greg Ungerer71.95%233.33%
Mike Frysinger10.28%116.67%
Total359100.00%6100.00%

/****************************************************************************/ #ifdef CONFIG_BINFMT_ZFLAT #include <linux/zlib.h> #define LBUFSIZE 4000 /* gzip flag byte */ #define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */ #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ #define COMMENT 0x10 /* bit 4 set: file comment present */ #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */ #define RESERVED 0xC0 /* bit 6,7: reserved */
static int decompress_exec(struct linux_binprm *bprm, loff_t fpos, char *dst, long len, int fd) { unsigned char *buf; z_stream strm; int ret, retval; pr_debug("decompress_exec(offset=%llx,buf=%p,len=%lx)\n", fpos, dst, len); memset(&strm, 0, sizeof(strm)); strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL); if (!strm.workspace) return -ENOMEM; buf = kmalloc(LBUFSIZE, GFP_KERNEL); if (!buf) { retval = -ENOMEM; goto out_free; } /* Read in first chunk of data and parse gzip header. */ ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos); strm.next_in = buf; strm.avail_in = ret; strm.total_in = 0; retval = -ENOEXEC; /* Check minimum size -- gzip header */ if (ret < 10) { pr_debug("file too small?\n"); goto out_free_buf; } /* Check gzip magic number */ if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) { pr_debug("unknown compression magic?\n"); goto out_free_buf; } /* Check gzip method */ if (buf[2] != 8) { pr_debug("unknown compression method?\n"); goto out_free_buf; } /* Check gzip flags */ if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) || (buf[3] & RESERVED)) { pr_debug("unknown flags?\n"); goto out_free_buf; } ret = 10; if (buf[3] & EXTRA_FIELD) { ret += 2 + buf[10] + (buf[11] << 8); if (unlikely(ret >= LBUFSIZE)) { pr_debug("buffer overflow (EXTRA)?\n"); goto out_free_buf; } } if (buf[3] & ORIG_NAME) { while (ret < LBUFSIZE && buf[ret++] != 0) ; if (unlikely(ret == LBUFSIZE)) { pr_debug("buffer overflow (ORIG_NAME)?\n"); goto out_free_buf; } } if (buf[3] & COMMENT) { while (ret < LBUFSIZE && buf[ret++] != 0) ; if (unlikely(ret == LBUFSIZE)) { pr_debug("buffer overflow (COMMENT)?\n"); goto out_free_buf; } } strm.next_in += ret; strm.avail_in -= ret; strm.next_out = dst; strm.avail_out = len; strm.total_out = 0; if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) { pr_debug("zlib init failed?\n"); goto out_free_buf; } while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) { ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos); if (ret <= 0) break; len -= ret; strm.next_in = buf; strm.avail_in = ret; strm.total_in = 0; } if (ret < 0) { pr_debug("decompression failed (%d), %s\n", ret, strm.msg); goto out_zlib; } retval = 0; out_zlib: zlib_inflateEnd(&strm); out_free_buf: kfree(buf); out_free: kfree(strm.workspace); return retval; }

Contributors

PersonTokensPropCommitsCommitProp
Alan Cox43374.91%111.11%
Greg Ungerer9816.96%222.22%
Nico Pitre254.33%222.22%
Christoph Hellwig101.73%111.11%
Volodymyr G. Lukiianyk81.38%111.11%
Al Viro20.35%111.11%
SF Markus Elfring20.35%111.11%
Total578100.00%9100.00%

#endif /* CONFIG_BINFMT_ZFLAT */ /****************************************************************************/
static unsigned long calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp) { unsigned long addr; int id; unsigned long start_brk; unsigned long start_data; unsigned long text_len; unsigned long start_code; #ifdef CONFIG_BINFMT_SHARED_FLAT if (r == 0) id = curid; /* Relocs of 0 are always self referring */ else { id = (r >> 24) & 0xff; /* Find ID for this reloc */ r &= 0x00ffffff; /* Trim ID off here */ } if (id >= MAX_SHARED_LIBS) { pr_err("reference 0x%lx to shared library %d", r, id); goto failed; } if (curid != id) { if (internalp) { pr_err("reloc address 0x%lx not in same module " "(%d != %d)", r, curid, id); goto failed; } else if (!p->lib_list[id].loaded && load_flat_shared_library(id, p) < 0) { pr_err("failed to load library %d", id); goto failed; } /* Check versioning information (i.e. time stamps) */ if (p->lib_list[id].build_date && p->lib_list[curid].build_date && p->lib_list[curid].build_date < p->lib_list[id].build_date) { pr_err("library %d is younger than %d", id, curid); goto failed; } } #else id = 0; #endif start_brk = p->lib_list[id].start_brk; start_data = p->lib_list[id].start_data; start_code = p->lib_list[id].start_code; text_len = p->lib_list[id].text_len; if (!flat_reloc_valid(r, start_brk - start_data + text_len)) { pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)", r, start_brk-start_data+text_len, text_len); goto failed; } if (r < text_len) /* In text segment */ addr = r + start_code; else /* In data segment */ addr = r - text_len + start_data; /* Range checked already above so doing the range tests is redundant...*/ return addr; failed: pr_cont(", killing %s!\n", current->comm); send_sig(SIGSEGV, current, 0); return RELOC_FAILED; }

Contributors

PersonTokensPropCommitsCommitProp
Greg Ungerer26174.57%120.00%
Alan Cox7320.86%120.00%
Nico Pitre113.14%120.00%
Jun Sun30.86%120.00%
Arnd Bergmann20.57%120.00%
Total350100.00%5100.00%

/****************************************************************************/
static void old_reloc(unsigned long rl) { static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" }; flat_v2_reloc_t r; unsigned long __user *ptr; unsigned long val; r.value = rl; #if defined(CONFIG_COLDFIRE) ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset); #else ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset); #endif get_user(val, ptr); pr_debug("Relocation of variable at DATASEG+%x " "(address %p, currently %lx) into segment %s\n", r.reloc.offset, ptr, val, segment[r.reloc.type]); switch (r.reloc.type) { case OLD_FLAT_RELOC_TYPE_TEXT: val += current->mm->start_code; break; case OLD_FLAT_RELOC_TYPE_DATA: val += current->mm->start_data; break; case OLD_FLAT_RELOC_TYPE_BSS: val += current->mm->end_data; break; default: pr_err("Unknown relocation type=%x\n", r.reloc.type); break; } put_user(val, ptr); pr_debug("Relocation became %lx\n", val); }

Contributors

PersonTokensPropCommitsCommitProp
Alan Cox17082.93%120.00%
Nico Pitre3416.59%360.00%
Axel Lin10.49%120.00%
Total205100.00%5100.00%

/****************************************************************************/
static int load_flat_file(struct linux_binprm *bprm, struct lib_info *libinfo, int id, unsigned long *extra_stack) { struct flat_hdr *hdr; unsigned long textpos, datapos, realdatastart; u32 text_len, data_len, bss_len, stack_len, full_data, flags; unsigned long len, memp, memp_size, extra, rlim; u32 __user *reloc, *rp; struct inode *inode; int i, rev, relocs; loff_t fpos; unsigned long start_code, end_code; ssize_t result; int ret; hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */ inode = file_inode(bprm->file); text_len = ntohl(hdr->data_start); data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start); bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end); stack_len = ntohl(hdr->stack_size); if (extra_stack) { stack_len += *extra_stack; *extra_stack = stack_len; } relocs = ntohl(hdr->reloc_count); flags = ntohl(hdr->flags); rev = ntohl(hdr->rev); full_data = data_len + relocs * sizeof(unsigned long); if (strncmp(hdr->magic, "bFLT", 4)) { /* * Previously, here was a printk to tell people * "BINFMT_FLAT: bad header magic". * But for the kernel which also use ELF FD-PIC format, this * error message is confusing. * because a lot of people do not manage to produce good */ ret = -ENOEXEC; goto err; } if (flags & FLAT_FLAG_KTRACE) pr_info("Loading file: %s\n", bprm->filename); if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) { pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n", rev, FLAT_VERSION, OLD_FLAT_VERSION); ret = -ENOEXEC; goto err; } /* Don't allow old format executables to use shared libraries */ if (rev == OLD_FLAT_VERSION && id != 0) { pr_err("shared libraries are not available before rev 0x%lx\n", FLAT_VERSION); ret = -ENOEXEC; goto err; } /* * Make sure the header params are sane. * 28 bits (256 MB) is way more than reasonable in this case. * If some top bits are set we have probable binary corruption. */ if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) { pr_err("bad header\n"); ret = -ENOEXEC; goto err; } /* * fix up the flags for the older format, there were all kinds * of endian hacks, this only works for the simple cases */ if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags)) flags = FLAT_FLAG_RAM; #ifndef CONFIG_BINFMT_ZFLAT if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) { pr_err("Support for ZFLAT executables is not enabled.\n"); ret = -ENOEXEC; goto err; } #endif /* * Check initial limits. This avoids letting people circumvent * size limits imposed on them by creating programs with large * arrays in the data or bss. */ rlim = rlimit(RLIMIT_DATA); if (rlim >= RLIM_INFINITY) rlim = ~0; if (data_len + bss_len > rlim) { ret = -ENOMEM; goto err; } /* Flush all traces of the currently running executable */ if (id == 0) { ret = flush_old_exec(bprm); if (ret) goto err; /* OK, This is the point of no return */ set_personality(PER_LINUX_32BIT); setup_new_exec(bprm); } /* * calculate the extra space we need to map in */ extra = max_t(unsigned long, bss_len + stack_len, relocs * sizeof(unsigned long)); /* * there are a couple of cases here, the separate code/data * case, and then the fully copied to RAM case which lumps * it all together. */ if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) { /* * this should give us a ROM ptr, but if it doesn't we don't * really care */ pr_debug("ROM mapping of file (we hope)\n"); textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_EXECUTABLE, 0); if (!textpos || IS_ERR_VALUE(textpos)) { ret = textpos; if (!textpos) ret = -ENOMEM; pr_err("Unable to mmap process text, errno %d\n", ret); goto err; } len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long); len = PAGE_ALIGN(len); realdatastart = vm_mmap(NULL, 0, len, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0); if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) { ret = realdatastart; if (!realdatastart) ret = -ENOMEM; pr_err("Unable to allocate RAM for process data, " "errno %d\n", ret); vm_munmap(textpos, text_len); goto err; } datapos = ALIGN(realdatastart + MAX_SHARED_LIBS * sizeof(unsigned long), FLAT_DATA_ALIGN); pr_debug("Allocated data+bss+stack (%u bytes): %lx\n", data_len + bss_len + stack_len, datapos); fpos = ntohl(hdr->data_start); #ifdef CONFIG_BINFMT_ZFLAT if (flags & FLAT_FLAG_GZDATA) { result = decompress_exec(bprm, fpos, (char *)datapos, full_data, 0); } else #endif { result = read_code(bprm->file, datapos, fpos, full_data); } if (IS_ERR_VALUE(result)) { ret = result; pr_err("Unable to read data+bss, errno %d\n", ret); vm_munmap(textpos, text_len); vm_munmap(realdatastart, len); goto err; } reloc = (u32 __user *) (datapos + (ntohl(hdr->reloc_start) - text_len)); memp = realdatastart; memp_size = len; } else { len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(u32); len = PAGE_ALIGN(len); textpos = vm_mmap(NULL, 0, len, PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0); if (!textpos || IS_ERR_VALUE(textpos)) { ret = textpos; if (!textpos) ret = -ENOMEM; pr_err("Unable to allocate RAM for process text/data, " "errno %d\n", ret); goto err; } realdatastart = textpos + ntohl(hdr->data_start); datapos = ALIGN(realdatastart + MAX_SHARED_LIBS * sizeof(u32), FLAT_DATA_ALIGN); reloc = (u32 __user *) (datapos + (ntohl(hdr->reloc_start) - text_len)); memp = textpos; memp_size = len; #ifdef CONFIG_BINFMT_ZFLAT /* * load it all in and treat it like a RAM load from now on */ if (flags & FLAT_FLAG_GZIP) { #ifndef CONFIG_MMU result = decompress_exec(bprm, sizeof(struct flat_hdr), (((char *)textpos) + sizeof(struct flat_hdr)), (text_len + full_data - sizeof(struct flat_hdr)), 0); memmove((void *) datapos, (void *) realdatastart, full_data); #else /* * This is used on MMU systems mainly for testing. * Let's use a kernel buffer to simplify things. */ long unz_text_len = text_len - sizeof(struct flat_hdr); long unz_len = unz_text_len + full_data; char *unz_data = vmalloc(unz_len); if (!unz_data) { result = -ENOMEM; } else { result = decompress_exec(bprm, sizeof(struct flat_hdr), unz_data, unz_len, 0); if (result == 0 && (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr), unz_data, unz_text_len) || copy_to_user((void __user *)datapos, unz_data + unz_text_len, full_data))) result = -EFAULT; vfree(unz_data); } #endif } else if (flags & FLAT_FLAG_GZDATA) { result = read_code(bprm->file, textpos, 0, text_len); if (!IS_ERR_VALUE(result)) { #ifndef CONFIG_MMU result = decompress_exec(bprm, text_len, (char *) datapos, full_data, 0); #else char *unz_data = vmalloc(full_data); if (!unz_data) { result = -ENOMEM; } else { result = decompress_exec(bprm, text_len, unz_data, full_data, 0); if (result == 0 && copy_to_user((void __user *)datapos, unz_data, full_data)) result = -EFAULT; vfree(unz_data); } #endif } } else #endif /* CONFIG_BINFMT_ZFLAT */ { result = read_code(bprm->file, textpos, 0, text_len); if (!IS_ERR_VALUE(result)) result = read_code(bprm->file, datapos, ntohl(hdr->data_start), full_data); } if (IS_ERR_VALUE(result)) { ret = result; pr_err("Unable to read code+data+bss, errno %d\n", ret); vm_munmap(textpos, text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(u32)); goto err; } } start_code = textpos + sizeof(struct flat_hdr); end_code = textpos + text_len; text_len -= sizeof(struct flat_hdr); /* the real code len */ /* The main program needs a little extra setup in the task structure */ if (id == 0) { current->mm->start_code = start_code; current->mm->end_code = end_code; current->mm->start_data = datapos; current->mm->end_data = datapos + data_len; /* * set up the brk stuff, uses any slack left in data/bss/stack * allocation. We put the brk after the bss (between the bss * and stack) like other platforms. * Userspace code relies on the stack pointer starting out at * an address right at the end of a page. */ current->mm->start_brk = datapos + data_len + bss_len; current->mm->brk = (current->mm->start_brk + 3) & ~3; #ifndef CONFIG_MMU current->mm->context.end_brk = memp + memp_size - stack_len; #endif } if (flags & FLAT_FLAG_KTRACE) { pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n", textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start)); pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n", id ? "Lib" : "Load", bprm->filename, start_code, end_code, datapos, datapos + data_len, datapos + data_len, (datapos + data_len + bss_len + 3) & ~3); } /* Store the current module values into the global library structure */ libinfo->lib_list[id].start_code = start_code; libinfo->lib_list[id].start_data = datapos; libinfo->lib_list[id].start_brk = datapos + data_len + bss_len; libinfo->lib_list[id].text_len = text_len; libinfo->lib_list[id].loaded = 1; libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos; libinfo->lib_list[id].build_date = ntohl(hdr->build_date); /* * We just load the allocations into some temporary memory to * help simplify all this mumbo jumbo * * We've got two different sections of relocation entries. * The first is the GOT which resides at the beginning of the data segment * and is terminated with a -1. This one can be relocated in place. * The second is the extra relocation entries tacked after the image's * data segment. These require a little more processing as the entry is * really an offset into the image which contains an offset into the * image. */ if (flags & FLAT_FLAG_GOTPIC) { for (rp = (u32 __user *)datapos; ; rp++) { u32 addr, rp_val; if (get_user(rp_val, rp)) return -EFAULT; if (rp_val == 0xffffffff) break; if (rp_val) { addr = calc_reloc(rp_val, libinfo, id, 0); if (addr == RELOC_FAILED) { ret = -ENOEXEC; goto err; } if (put_user(addr, rp)) return -EFAULT; } } } /* * Now run through the relocation entries. * We've got to be careful here as C++ produces relocatable zero * entries in the constructor and destructor tables which are then * tested for being not zero (which will always occur unless we're * based from address zero). This causes an endless loop as __start * is at zero. The solution used is to not relocate zero addresses. * This has the negative side effect of not allowing a global data * reference to be statically initialised to _stext (I've moved * __start to address 4 so that is okay). */ if (rev > OLD_FLAT_VERSION) { u32 __maybe_unused persistent = 0; for (i = 0; i < relocs; i++) { u32 addr, relval; /* * Get the address of the pointer to be * relocated (of course, the address has to be * relocated first). */ if (get_user(relval, reloc + i)) return -EFAULT; relval = ntohl(relval); if (flat_set_persistent(relval, &persistent)) continue; addr = flat_get_relocate_addr(relval); rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1); if (rp == (u32 __user *)RELOC_FAILED) { ret = -ENOEXEC; goto err; } /* Get the pointer's value. */ ret = flat_get_addr_from_rp(rp, relval, flags, &addr, &persistent); if (unlikely(ret)) goto err; if (addr != 0) { /* * Do the relocation. PIC relocs in the data section are * already in target order */ if ((flags & FLAT_FLAG_GOTPIC) == 0) addr = ntohl(addr); addr = calc_reloc(addr, libinfo, id, 0); if (addr == RELOC_FAILED) { ret = -ENOEXEC; goto err; } /* Write back the relocated pointer. */ ret = flat_put_addr_at_rp(rp, addr, relval); if (unlikely(ret)) goto err; } } } else { for (i = 0; i < relocs; i++) { u32 relval; if (get_user(relval, reloc + i)) return -EFAULT; relval = ntohl(relval); old_reloc(relval); } } flush_icache_range(start_code, end_code); /* zero the BSS, BRK and stack areas */ if (clear_user((void __user *)(datapos + data_len), bss_len + (memp + memp_size - stack_len - /* end brk */ libinfo->lib_list[id].start_brk) + /* start brk */ stack_len)) return -EFAULT; return 0; err: return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Alan Cox82939.78%25.56%
Greg Ungerer53325.58%411.11%
Nico Pitre43320.78%822.22%
Al Viro934.46%411.11%
Luke Yang783.74%12.78%
David Howells271.30%12.78%
Mike Frysinger251.20%38.33%
Bernd Schmidt180.86%12.78%
Andrew Morton160.77%38.33%
Oskar Schirmer140.67%12.78%
Linus Torvalds80.38%25.56%
Jiri Slaby30.14%12.78%
Yoshinori Sato20.10%12.78%
Matt Helsley20.10%12.78%
Geert Uytterhoeven10.05%12.78%
Malcolm Parsons10.05%12.78%
Lucas De Marchi10.05%12.78%
Total2084100.00%36100.00%

/****************************************************************************/ #ifdef CONFIG_BINFMT_SHARED_FLAT /* * Load a shared library into memory. The library gets its own data * segment (including bss) but not argv/argc/environ. */
static int load_flat_shared_library(int id, struct lib_info *libs) { struct linux_binprm bprm; int res; char buf[16]; memset(&bprm, 0, sizeof(bprm)); /* Create the file name */ sprintf(buf, "/lib/lib%d.so", id); /* Open the file up */ bprm.filename = buf; bprm.file = open_exec(bprm.filename); res = PTR_ERR(bprm.file); if (IS_ERR(bprm.file)) return res; bprm.cred = prepare_exec_creds(); res = -ENOMEM; if (!bprm.cred) goto out; /* We don't really care about recalculating credentials at this point * as we're past the point of no return and are dealing with shared * libraries. */ bprm.called_set_creds = 1; res = prepare_binprm(&bprm); if (!res) res = load_flat_file(&bprm, libs, id, NULL); abort_creds(bprm.cred); out: allow_write_access(bprm.file); fput(bprm.file); return res; }

Contributors

PersonTokensPropCommitsCommitProp
Greg Ungerer12170.76%120.00%
Linus Torvalds2916.96%120.00%
David Howells1911.11%120.00%
Kees Cook10.58%120.00%
Mike Frysinger10.58%120.00%
Total171100.00%5100.00%

#endif /* CONFIG_BINFMT_SHARED_FLAT */ /****************************************************************************/ /* * These are the functions used to load flat style executables and shared * libraries. There is no binary dependent code anywhere else. */
static int load_flat_binary(struct linux_binprm *bprm) { struct lib_info libinfo; struct pt_regs *regs = current_pt_regs(); unsigned long stack_len = 0; unsigned long start_addr; int res; int i, j; memset(&libinfo, 0, sizeof(libinfo)); /* * We have to add the size of our arguments to our stack size * otherwise it's too easy for users to create stack overflows * by passing in a huge argument list. And yes, we have to be * pedantic and include space for the argv/envp array as it may have * a lot of entries. */ #ifndef CONFIG_MMU stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */ #endif stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */ stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */ stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN); res = load_flat_file(bprm, &libinfo, 0, &stack_len); if (res < 0) return res; /* Update data segment pointers for all libraries */ for (i = 0; i < MAX_SHARED_LIBS; i++) { if (!libinfo.lib_list[i].loaded) continue; for (j = 0; j < MAX_SHARED_LIBS; j++) { unsigned long val = libinfo.lib_list[j].loaded ? libinfo.lib_list[j].start_data : UNLOADED_LIB; unsigned long __user *p = (unsigned long __user *) libinfo.lib_list[i].start_data; p -= j + 1; if (put_user(val, p)) return -EFAULT; } } install_exec_creds(bprm); set_binfmt(&flat_format); #ifdef CONFIG_MMU res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); if (!res) res = create_flat_tables(bprm, bprm->p); #else /* Stash our initial stack pointer into the mm structure */ current->mm->start_stack = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4; pr_debug("sp=%lx\n", current->mm->start_stack); /* copy the arg pages onto the stack */ res = transfer_args_to_stack(bprm, &current->mm->start_stack); if (!res) res = create_flat_tables(bprm, current->mm->start_stack); #endif if (res) return res; /* Fake some return addresses to ensure the call chain will * initialise library in order for us. We are required to call * lib 1 first, then 2, ... and finally the main program (id 0). */ start_addr = libinfo.lib_list[0].entry; #ifdef CONFIG_BINFMT_SHARED_FLAT for (i = MAX_SHARED_LIBS-1; i > 0; i--) { if (libinfo.lib_list[i].loaded) { /* Push previos first to call address */ unsigned long __user *sp; current->mm->start_stack -= sizeof(unsigned long); sp = (unsigned long __user *)current->mm->start_stack; __put_user(start_addr, sp); start_addr = libinfo.lib_list[i].entry; } } #endif #ifdef FLAT_PLAT_INIT FLAT_PLAT_INIT(regs); #endif pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n", regs, start_addr, current->mm->start_stack); start_thread(regs, start_addr, current->mm->start_stack); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Greg Ungerer21141.45%17.14%
Nico Pitre17534.38%642.86%
Alan Cox9919.45%17.14%
Takashi Yoshii101.96%17.14%
Al Viro81.57%17.14%
Oskar Schirmer20.39%17.14%
Arnd Bergmann20.39%17.14%
Mike Frysinger10.20%17.14%
David Howells10.20%17.14%
Total509100.00%14100.00%

/****************************************************************************/
static int __init init_flat_binfmt(void) { register_binfmt(&flat_format); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Alan Cox1583.33%150.00%
Al Viro316.67%150.00%
Total18100.00%2100.00%

core_initcall(init_flat_binfmt); /****************************************************************************/

Overall Contributors

PersonTokensPropCommitsCommitProp
Alan Cox190541.49%23.28%
Greg Ungerer136629.75%69.84%
Nico Pitre87118.97%1118.03%
Al Viro1062.31%69.84%
Luke Yang801.74%11.64%
Oskar Schirmer471.02%11.64%
David Howells471.02%34.92%
Linus Torvalds370.81%34.92%
Mike Frysinger360.78%58.20%
Bernd Schmidt180.39%11.64%
Andrew Morton170.37%46.56%
Takashi Yoshii100.22%11.64%
Christoph Hellwig100.22%11.64%
Volodymyr G. Lukiianyk80.17%11.64%
Masami Hiramatsu60.13%11.64%
Arnd Bergmann40.09%11.64%
Denys Vlasenko30.07%11.64%
Jiri Slaby30.07%11.64%
Ingo Molnar30.07%11.64%
Jun Sun30.07%11.64%
Matt Helsley20.04%11.64%
SF Markus Elfring20.04%11.64%
Yoshinori Sato20.04%11.64%
Malcolm Parsons10.02%11.64%
Lucas De Marchi10.02%11.64%
Greg Kroah-Hartman10.02%11.64%
Geert Uytterhoeven10.02%11.64%
Kees Cook10.02%11.64%
Axel Lin10.02%11.64%
Total4592100.00%61100.00%
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