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-rw-r--r--fs/exec.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 4007314228..0c17e59e37 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1668,6 +1668,7 @@ static void bprm_fill_uid(struct linux_binprm *bprm, struct file *file)
unsigned int mode;
vfsuid_t vfsuid;
vfsgid_t vfsgid;
+ int err;
if (!mnt_may_suid(file->f_path.mnt))
return;
@@ -1684,12 +1685,17 @@ static void bprm_fill_uid(struct linux_binprm *bprm, struct file *file)
/* Be careful if suid/sgid is set */
inode_lock(inode);
- /* reload atomically mode/uid/gid now that lock held */
+ /* Atomically reload and check mode/uid/gid now that lock held. */
mode = inode->i_mode;
vfsuid = i_uid_into_vfsuid(idmap, inode);
vfsgid = i_gid_into_vfsgid(idmap, inode);
+ err = inode_permission(idmap, inode, MAY_EXEC);
inode_unlock(inode);
+ /* Did the exec bit vanish out from under us? Give up. */
+ if (err)
+ return;
+
/* We ignore suid/sgid if there are no mappings for them in the ns */
if (!vfsuid_has_mapping(bprm->cred->user_ns, vfsuid) ||
!vfsgid_has_mapping(bprm->cred->user_ns, vfsgid))