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authorKirill A. Shutemov <kirill@shutemov.name>2008-10-16 07:02:39 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-16 20:21:38 +0200
commitbf2a9a39639b8b51377905397a5005f444e9a892 (patch)
tree1919ad1abea804ce4cb1e7e8b1ac44b5b9a8f110 /fs/binfmt_script.c
parentalpha: introduce field 'taso' into struct linux_binprm (diff)
downloadlinux-bf2a9a39639b8b51377905397a5005f444e9a892.tar.xz
linux-bf2a9a39639b8b51377905397a5005f444e9a892.zip
Allow recursion in binfmt_script and binfmt_misc
binfmt_script and binfmt_misc disallow recursion to avoid stack overflow using sh_bang and misc_bang. It causes problem in some cases: $ echo '#!/bin/ls' > /tmp/t0 $ echo '#!/tmp/t0' > /tmp/t1 $ echo '#!/tmp/t1' > /tmp/t2 $ chmod +x /tmp/t* $ /tmp/t2 zsh: exec format error: /tmp/t2 Similar problem with binfmt_misc. This patch introduces field 'recursion_depth' into struct linux_binprm to track recursion level in binfmt_misc and binfmt_script. If recursion level more then BINPRM_MAX_RECURSION it generates -ENOEXEC. [akpm@linux-foundation.org: make linux_binprm.recursion_depth a uint] Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Pavel Emelyanov <xemul@openvz.org> 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>
Diffstat (limited to 'fs/binfmt_script.c')
-rw-r--r--fs/binfmt_script.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/binfmt_script.c b/fs/binfmt_script.c
index 9e3963f7ebf1..08343505e184 100644
--- a/fs/binfmt_script.c
+++ b/fs/binfmt_script.c
@@ -22,14 +22,15 @@ static int load_script(struct linux_binprm *bprm,struct pt_regs *regs)
char interp[BINPRM_BUF_SIZE];
int retval;
- if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!') || (bprm->sh_bang))
+ if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!') ||
+ (bprm->recursion_depth > BINPRM_MAX_RECURSION))
return -ENOEXEC;
/*
* This section does the #! interpretation.
* Sorta complicated, but hopefully it will work. -TYT
*/
- bprm->sh_bang = 1;
+ bprm->recursion_depth++;
allow_write_access(bprm->file);
fput(bprm->file);
bprm->file = NULL;