diff options
| author | Kees Cook <keescook@chromium.org> | 2012-12-17 16:03:20 -0800 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2013-06-10 11:42:18 +0200 |
| commit | fa078af1f06731a76f76a2f5fd2dd4b4b1dc167e (patch) | |
| tree | b05976d3d323a4db4e7ea9495aad4996123f22ec /include | |
| parent | 59e376d0e4f12daf3817621c023e13556996c851 (diff) | |
exec: use -ELOOP for max recursion depth
commit d740269867021faf4ce38a449353d2b986c34a67 upstream
To avoid an explosion of request_module calls on a chain of abusive
scripts, fail maximum recursion with -ELOOP instead of -ENOEXEC. As soon
as maximum recursion depth is hit, the error will fail all the way back
up the chain, aborting immediately.
This also has the side-effect of stopping the user's shell from attempting
to reexecute the top-level file as a shell script. As seen in the
dash source:
if (cmd != path_bshell && errno == ENOEXEC) {
*argv-- = cmd;
*argv = cmd = path_bshell;
goto repeat;
}
The above logic was designed for running scripts automatically that lacked
the "#!" header, not to re-try failed recursion. On a legitimate -ENOEXEC,
things continue to behave as the shell expects.
Additionally, when tracking recursion, the binfmt handlers should not be
involved. The recursion being tracked is the depth of calls through
search_binary_handler(), so that function should be exclusively responsible
for tracking the depth.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: halfdog <me@halfdog.net>
Cc: P J P <ppandit@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[dannf: backported to Debian's 2.6.32]
Signed-off-by: Willy Tarreau <w@1wt.eu>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/binfmts.h | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h index d06c3a455e16..9ffffec7ba08 100644 --- a/include/linux/binfmts.h +++ b/include/linux/binfmts.h @@ -71,8 +71,6 @@ extern struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, #define BINPRM_FLAGS_EXECFD_BIT 1 #define BINPRM_FLAGS_EXECFD (1 << BINPRM_FLAGS_EXECFD_BIT) -#define BINPRM_MAX_RECURSION 4 - /* * This structure defines the functions that are used to load the binary formats that * linux accepts. |