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authorPavel Emelyanov <xemul@openvz.org>2008-04-29 11:59:24 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-29 19:06:04 +0400
commit3a2e7f47d71e1df86acc1dda6826890b6546a4e1 (patch)
tree3c5856f67af25a80a4d934e754f437936c7b1bbf /include/linux/binfmts.h
parentcbd9b67bd3883dff0ef4b8ec9229d315a9ba38f0 (diff)
downloadlinux-3a2e7f47d71e1df86acc1dda6826890b6546a4e1.tar.xz
binfmt_misc.c: avoid potential kernel stack overflow
This can be triggered with root help only, but... Register the ":text:E::txt::/root/cat.txt:' rule in binfmt_misc (by root) and try launching the cat.txt file (by anyone) :) The result is - the endless recursion in the load_misc_binary -> open_exec -> load_misc_binary chain and stack overflow. There's a similar problem with binfmt_script, and there's a sh_bang memner on linux_binprm structure to handle this, but simply raising this in binfmt_misc may break some setups when the interpreter of some misc binaries is a script. So the proposal is to turn sh_bang into a bit, add a new one (the misc_bang) and raise it in load_misc_binary. After this, even if we set up the misc -> script -> misc loop for binfmts one of them will step on its own bang and exit. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/binfmts.h')
-rw-r--r--include/linux/binfmts.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index 1dd756731c95..b512e48f6d8e 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -34,7 +34,8 @@ struct linux_binprm{
#endif
struct mm_struct *mm;
unsigned long p; /* current top of mem */
- int sh_bang;
+ unsigned int sh_bang:1,
+ misc_bang:1;
struct file * file;
int e_uid, e_gid;
kernel_cap_t cap_inheritable, cap_permitted;