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| author | Al Viro <viro@zeniv.linux.org.uk> | 2020-03-05 19:34:48 +0300 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2020-04-02 08:09:27 +0300 |
| commit | 0f705953012a753068b20016f55dc12d1f7e17e5 (patch) | |
| tree | a7a0082ab31848427122ae949f8fafab63c6666c /fs/namei.c | |
| parent | 60ef60c7d7291d7cdc43661363cd05a5102e69f6 (diff) | |
| download | linux-0f705953012a753068b20016f55dc12d1f7e17e5.tar.xz | |
link_path_walk(): sample parent's i_uid and i_mode for the last component
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 17 |
1 files changed, 7 insertions, 10 deletions
diff --git a/fs/namei.c b/fs/namei.c index 7a95a3fcbf68..e737d884592d 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -505,6 +505,8 @@ struct nameidata { struct nameidata *saved; unsigned root_seq; int dfd; + kuid_t dir_uid; + umode_t dir_mode; } __randomize_layout; static void set_nameidata(struct nameidata *p, int dfd, struct filename *name) @@ -938,9 +940,6 @@ int sysctl_protected_regular __read_mostly; */ static inline int may_follow_link(struct nameidata *nd, const struct inode *inode) { - const struct inode *parent; - kuid_t puid; - if (!sysctl_protected_symlinks) return 0; @@ -949,13 +948,11 @@ static inline int may_follow_link(struct nameidata *nd, const struct inode *inod return 0; /* Allowed if parent directory not sticky and world-writable. */ - parent = nd->inode; - if ((parent->i_mode & (S_ISVTX|S_IWOTH)) != (S_ISVTX|S_IWOTH)) + if ((nd->dir_mode & (S_ISVTX|S_IWOTH)) != (S_ISVTX|S_IWOTH)) return 0; /* Allowed if parent directory and link owner match. */ - puid = parent->i_uid; - if (uid_valid(puid) && uid_eq(puid, inode->i_uid)) + if (uid_valid(nd->dir_uid) && uid_eq(nd->dir_uid, inode->i_uid)) return 0; if (nd->flags & LOOKUP_RCU) @@ -2159,6 +2156,8 @@ static int link_path_walk(const char *name, struct nameidata *nd) OK: /* pathname or trailing symlink, done */ if (!depth) { + nd->dir_uid = nd->inode->i_uid; + nd->dir_mode = nd->inode->i_mode; nd->flags &= ~LOOKUP_PARENT; return 0; } @@ -3224,8 +3223,6 @@ finish_lookup: static const char *do_last(struct nameidata *nd, struct file *file, const struct open_flags *op) { - kuid_t dir_uid = nd->inode->i_uid; - umode_t dir_mode = nd->inode->i_mode; int open_flag = op->open_flag; bool do_truncate; int acc_mode; @@ -3241,7 +3238,7 @@ static const char *do_last(struct nameidata *nd, if (open_flag & O_CREAT) { if (d_is_dir(nd->path.dentry)) return ERR_PTR(-EISDIR); - error = may_create_in_sticky(dir_mode, dir_uid, + error = may_create_in_sticky(nd->dir_mode, nd->dir_uid, d_backing_inode(nd->path.dentry)); if (unlikely(error)) return ERR_PTR(error); |