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authorLinus Torvalds <torvalds@linux-foundation.org>2016-12-14 14:09:48 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-14 14:09:48 -0800
commit412ac77a9d3ec015524dacea905471d66480b7ac (patch)
tree28ae7e4f3aaeab5411a11818d03b3722a31ecf36 /fs/exec.c
parentdcdaa2f9480c55c6dcf54ab480e82e93e5622318 (diff)
parent19339c251607a3defc7f089511ce8561936fee45 (diff)
downloadlinux-412ac77a9d3ec015524dacea905471d66480b7ac.tar.bz2
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace updates from Eric Biederman: "After a lot of discussion and work we have finally reachanged a basic understanding of what is necessary to make unprivileged mounts safe in the presence of EVM and IMA xattrs which the last commit in this series reflects. While technically it is a revert the comments it adds are important for people not getting confused in the future. Clearing up that confusion allows us to seriously work on unprivileged mounts of fuse in the next development cycle. The rest of the fixes in this set are in the intersection of user namespaces, ptrace, and exec. I started with the first fix which started a feedback cycle of finding additional issues during review and fixing them. Culiminating in a fix for a bug that has been present since at least Linux v1.0. Potentially these fixes were candidates for being merged during the rc cycle, and are certainly backport candidates but enough little things turned up during review and testing that I decided they should be handled as part of the normal development process just to be certain there were not any great surprises when it came time to backport some of these fixes" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: Revert "evm: Translate user/group ids relative to s_user_ns when computing HMAC" exec: Ensure mm->user_ns contains the execed files ptrace: Don't allow accessing an undumpable mm ptrace: Capture the ptracer's creds not PT_PTRACE_CAP mm: Add a user_ns owner to mm_struct and fix ptrace permission checks
Diffstat (limited to 'fs/exec.c')
-rw-r--r--fs/exec.c21
1 files changed, 18 insertions, 3 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 923c57d96899..88b5e1efdbd6 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1277,8 +1277,22 @@ EXPORT_SYMBOL(flush_old_exec);
void would_dump(struct linux_binprm *bprm, struct file *file)
{
- if (inode_permission(file_inode(file), MAY_READ) < 0)
+ struct inode *inode = file_inode(file);
+ if (inode_permission(inode, MAY_READ) < 0) {
+ struct user_namespace *old, *user_ns;
bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
+
+ /* Ensure mm->user_ns contains the executable */
+ user_ns = old = bprm->mm->user_ns;
+ while ((user_ns != &init_user_ns) &&
+ !privileged_wrt_inode_uidgid(user_ns, inode))
+ user_ns = user_ns->parent;
+
+ if (old != user_ns) {
+ bprm->mm->user_ns = get_user_ns(user_ns);
+ put_user_ns(old);
+ }
+ }
}
EXPORT_SYMBOL(would_dump);
@@ -1308,7 +1322,6 @@ void setup_new_exec(struct linux_binprm * bprm)
!gid_eq(bprm->cred->gid, current_egid())) {
current->pdeath_signal = 0;
} else {
- would_dump(bprm, bprm->file);
if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)
set_dumpable(current->mm, suid_dumpable);
}
@@ -1408,7 +1421,7 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
unsigned n_fs;
if (p->ptrace) {
- if (p->ptrace & PT_PTRACE_CAP)
+ if (ptracer_capable(p, current_user_ns()))
bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP;
else
bprm->unsafe |= LSM_UNSAFE_PTRACE;
@@ -1743,6 +1756,8 @@ static int do_execveat_common(int fd, struct filename *filename,
if (retval < 0)
goto out;
+ would_dump(bprm, bprm->file);
+
retval = exec_binprm(bprm);
if (retval < 0)
goto out;