cregit-Linux how code gets into the kernel

Release 4.7 fs/attr.c

Directory: fs
/*
 *  linux/fs/attr.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  changes by Thomas Schoebel-Theuer
 */

#include <linux/export.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/capability.h>
#include <linux/fsnotify.h>
#include <linux/fcntl.h>
#include <linux/security.h>
#include <linux/evm.h>
#include <linux/ima.h>

/**
 * inode_change_ok - check if attribute changes to an inode are allowed
 * @inode:      inode to check
 * @attr:       attributes to change
 *
 * Check if we are allowed to change the attributes contained in @attr
 * in the given inode.  This includes the normal unix access permission
 * checks, as well as checks for rlimits and others.
 *
 * Should be called as the first thing in ->setattr implementations,
 * possibly after taking additional locks.
 */

int inode_change_ok(const struct inode *inode, struct iattr *attr) { unsigned int ia_valid = attr->ia_valid; /* * First check size constraints. These can't be overriden using * ATTR_FORCE. */ if (ia_valid & ATTR_SIZE) { int error = inode_newsize_ok(inode, attr->ia_size); if (error) return error; } /* If force is set do it anyway. */ if (ia_valid & ATTR_FORCE) return 0; /* Make sure a caller can chown. */ if ((ia_valid & ATTR_UID) && (!uid_eq(current_fsuid(), inode->i_uid) || !uid_eq(attr->ia_uid, inode->i_uid)) && !capable_wrt_inode_uidgid(inode, CAP_CHOWN)) return -EPERM; /* Make sure caller can chgrp. */ if ((ia_valid & ATTR_GID) && (!uid_eq(current_fsuid(), inode->i_uid) || (!in_group_p(attr->ia_gid) && !gid_eq(attr->ia_gid, inode->i_gid))) && !capable_wrt_inode_uidgid(inode, CAP_CHOWN)) return -EPERM; /* Make sure a caller can chmod. */ if (ia_valid & ATTR_MODE) { if (!inode_owner_or_capable(inode)) return -EPERM; /* Also check the setgid bit! */ if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid : inode->i_gid) && !capable_wrt_inode_uidgid(inode, CAP_FSETID)) attr->ia_mode &= ~S_ISGID; } /* Check for setting the inode time. */ if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) { if (!inode_owner_or_capable(inode)) return -EPERM; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git15762.55%428.57%
christoph hellwigchristoph hellwig4819.12%17.14%
eric w. biedermaneric w. biederman2610.36%214.29%
chris wrightchris wright62.39%17.14%
david howellsdavid howells41.59%17.14%
andy lutomirskiandy lutomirski31.20%17.14%
satyam sharmasatyam sharma20.80%17.14%
miklos szeredimiklos szeredi20.80%17.14%
serge hallynserge hallyn20.80%17.14%
nick pigginnick piggin10.40%17.14%
Total251100.00%14100.00%

EXPORT_SYMBOL(inode_change_ok); /** * inode_newsize_ok - may this inode be truncated to a given size * @inode: the inode to be truncated * @offset: the new size to assign to the inode * @Returns: 0 on success, -ve errno on failure * * inode_newsize_ok must be called with i_mutex held. * * inode_newsize_ok will check filesystem limits and ulimits to check that the * new inode size is within limits. inode_newsize_ok will also send SIGXFSZ * when necessary. Caller must not proceed with inode size change if failure is * returned. @inode must be a file (not directory), with appropriate * permissions to allow truncate (inode_newsize_ok does NOT check these * conditions). */
int inode_newsize_ok(const struct inode *inode, loff_t offset) { if (inode->i_size < offset) { unsigned long limit; limit = rlimit(RLIMIT_FSIZE); if (limit != RLIM_INFINITY && offset > limit) goto out_sig; if (offset > inode->i_sb->s_maxbytes) goto out_big; } else { /* * truncation of in-use swapfiles is disallowed - it would * cause subsequent swapout to scribble on the now-freed * blocks. */ if (IS_SWAPFILE(inode)) return -ETXTBSY; } return 0; out_sig: send_sig(SIGXFSZ, current, 0); out_big: return -EFBIG; }

Contributors

PersonTokensPropCommitsCommitProp
nick pigginnick piggin9396.88%150.00%
jiri slabyjiri slaby33.12%150.00%
Total96100.00%2100.00%

EXPORT_SYMBOL(inode_newsize_ok); /** * setattr_copy - copy simple metadata updates into the generic inode * @inode: the inode to be updated * @attr: the new attributes * * setattr_copy must be called with i_mutex held. * * setattr_copy updates the inode's metadata with that specified * in attr. Noticeably missing is inode size update, which is more complex * as it requires pagecache updates. * * The inode is not marked as dirty after this operation. The rationale is * that for "simple" filesystems, the struct inode is the inode storage. * The caller is free to mark the inode dirty afterwards if needed. */
void setattr_copy(struct inode *inode, const struct iattr *attr) { unsigned int ia_valid = attr->ia_valid; if (ia_valid & ATTR_UID) inode->i_uid = attr->ia_uid; if (ia_valid & ATTR_GID) inode->i_gid = attr->ia_gid; if (ia_valid & ATTR_ATIME) inode->i_atime = timespec_trunc(attr->ia_atime, inode->i_sb->s_time_gran); if (ia_valid & ATTR_MTIME) inode->i_mtime = timespec_trunc(attr->ia_mtime, inode->i_sb->s_time_gran); if (ia_valid & ATTR_CTIME) inode->i_ctime = timespec_trunc(attr->ia_ctime, inode->i_sb->s_time_gran); if (ia_valid & ATTR_MODE) { umode_t mode = attr->ia_mode; if (!in_group_p(inode->i_gid) && !capable_wrt_inode_uidgid(inode, CAP_FSETID)) mode &= ~S_ISGID; inode->i_mode = mode; } }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git11267.88%541.67%
andi kleenandi kleen2716.36%18.33%
andrew mortonandrew morton116.67%18.33%
linus torvaldslinus torvalds84.85%18.33%
nick pigginnick piggin31.82%18.33%
eric w. biedermaneric w. biederman21.21%18.33%
christoph hellwigchristoph hellwig10.61%18.33%
andy lutomirskiandy lutomirski10.61%18.33%
Total165100.00%12100.00%

EXPORT_SYMBOL(setattr_copy); /** * notify_change - modify attributes of a filesytem object * @dentry: object affected * @iattr: new attributes * @delegated_inode: returns inode, if the inode is delegated * * The caller must hold the i_mutex on the affected object. * * If notify_change discovers a delegation in need of breaking, * it will return -EWOULDBLOCK and return a reference to the inode in * delegated_inode. The caller should then break the delegation and * retry. Because breaking a delegation may take a long time, the * caller should drop the i_mutex before doing so. * * Alternatively, a caller may pass NULL for delegated_inode. This may * be appropriate for callers that expect the underlying filesystem not * to be NFS exported. Also, passing NULL is fine for callers holding * the file open for write, as there can be no conflicting delegation in * that case. */
int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **delegated_inode) { struct inode *inode = dentry->d_inode; umode_t mode = inode->i_mode; int error; struct timespec now; unsigned int ia_valid = attr->ia_valid; WARN_ON_ONCE(!inode_is_locked(inode)); if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) { if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) return -EPERM; } if ((ia_valid & ATTR_MODE)) { umode_t amode = attr->ia_mode; /* Flag setting protected by i_mutex */ if (is_sxid(amode)) inode->i_flags &= ~S_NOSEC; } now = current_fs_time(inode->i_sb); attr->ia_ctime = now; if (!(ia_valid & ATTR_ATIME_SET)) attr->ia_atime = now; if (!(ia_valid & ATTR_MTIME_SET)) attr->ia_mtime = now; if (ia_valid & ATTR_KILL_PRIV) { attr->ia_valid &= ~ATTR_KILL_PRIV; ia_valid &= ~ATTR_KILL_PRIV; error = security_inode_need_killpriv(dentry); if (error > 0) error = security_inode_killpriv(dentry); if (error) return error; } /* * We now pass ATTR_KILL_S*ID to the lower level setattr function so * that the function has the ability to reinterpret a mode change * that's due to these bits. This adds an implicit restriction that * no function will ever call notify_change with both ATTR_MODE and * ATTR_KILL_S*ID set. */ if ((ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) && (ia_valid & ATTR_MODE)) BUG(); if (ia_valid & ATTR_KILL_SUID) { if (mode & S_ISUID) { ia_valid = attr->ia_valid |= ATTR_MODE; attr->ia_mode = (inode->i_mode & ~S_ISUID); } } if (ia_valid & ATTR_KILL_SGID) { if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { if (!(ia_valid & ATTR_MODE)) { ia_valid = attr->ia_valid |= ATTR_MODE; attr->ia_mode = inode->i_mode; } attr->ia_mode &= ~S_ISGID; } } if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID))) return 0; error = security_inode_setattr(dentry, attr); if (error) return error; error = try_break_deleg(inode, delegated_inode); if (error) return error; if (inode->i_op->setattr) error = inode->i_op->setattr(dentry, attr); else error = simple_setattr(dentry, attr); if (!error) { fsnotify_change(dentry, ia_valid); ima_inode_post_setattr(dentry); evm_inode_post_setattr(dentry, ia_valid); } return error; }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git11325.17%623.08%
al viroal viro9922.05%415.38%
miklos szeredimiklos szeredi4810.69%27.69%
serge hallynserge hallyn4710.47%13.85%
jeff laytonjeff layton357.80%13.85%
andi kleenandi kleen337.35%27.69%
j. bruce fieldsj. bruce fields224.90%13.85%
mimi zoharmimi zohar143.12%27.69%
chuck leverchuck lever122.67%13.85%
adrian bunkadrian bunk92.00%13.85%
andrew mortonandrew morton81.78%13.85%
dave hansendave hansen30.67%13.85%
robert loverobert love20.45%13.85%
stephen d. smalleystephen d. smalley20.45%13.85%
christoph hellwigchristoph hellwig20.45%13.85%
Total449100.00%26100.00%

EXPORT_SYMBOL(notify_change);

Overall Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git39638.98%1019.23%
nick pigginnick piggin10710.53%23.85%
al viroal viro999.74%47.69%
andi kleenandi kleen605.91%35.77%
christoph hellwigchristoph hellwig535.22%35.77%
miklos szeredimiklos szeredi504.92%35.77%
serge hallynserge hallyn494.82%23.85%
jeff laytonjeff layton353.44%11.92%
eric w. biedermaneric w. biederman282.76%23.85%
j. bruce fieldsj. bruce fields232.26%11.92%
mimi zoharmimi zohar201.97%23.85%
andrew mortonandrew morton191.87%23.85%
arnaldo carvalho de meloarnaldo carvalho de melo121.18%11.92%
chuck leverchuck lever121.18%11.92%
linus torvaldslinus torvalds100.98%23.85%
adrian bunkadrian bunk90.89%11.92%
chris wrightchris wright60.59%11.92%
david howellsdavid howells40.39%11.92%
andy lutomirskiandy lutomirski40.39%11.92%
jiri slabyjiri slaby30.30%11.92%
robert loverobert love30.30%11.92%
stephen d. smalleystephen d. smalley30.30%11.92%
randy dunlaprandy dunlap30.30%11.92%
dave hansendave hansen30.30%11.92%
satyam sharmasatyam sharma20.20%11.92%
paul gortmakerpaul gortmaker10.10%11.92%
dave jonesdave jones10.10%11.92%
lucas de marchilucas de marchi10.10%11.92%
Total1016100.00%52100.00%
Directory: fs
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