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authorKees Cook <keescook@chromium.org>2012-12-17 16:03:20 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-03-28 12:06:14 -0700
commitea8d2d19ad17ceafc883b86e448a405cf7808927 (patch)
treebf100c8195fda161c4b9f329cb6284f31a5656de /include
parent7396043fa475256bb61f1c9f901cfd3ed550a3cd (diff)
downloadlwn-ea8d2d19ad17ceafc883b86e448a405cf7808927.tar.gz
lwn-ea8d2d19ad17ceafc883b86e448a405cf7808927.zip
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> Cc: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/binfmts.h2
1 files changed, 0 insertions, 2 deletions
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index 384e37f6834f..718eb0bca6fc 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -67,8 +67,6 @@ struct linux_binprm {
#define BINPRM_FLAGS_EXECFD_BIT 1
#define BINPRM_FLAGS_EXECFD (1 << BINPRM_FLAGS_EXECFD_BIT)
-#define BINPRM_MAX_RECURSION 4
-
/* Function parameter for binfmt->coredump */
struct coredump_params {
long signr;