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authorKirill A. Shutemov <kirill@shutemov.name>2008-10-16 01:02:39 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-16 14:21:38 -0400
commitbf2a9a39639b8b51377905397a5005f444e9a892 (patch)
tree1919ad1abea804ce4cb1e7e8b1ac44b5b9a8f110 /fs/binfmt_misc.c
parent53112488bebe25c0f5f8a002470046c0fe9a6c61 (diff)
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_misc.c')
-rw-r--r--fs/binfmt_misc.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index 8d7e88e02e0f..f2744ab4e5b3 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -117,7 +117,7 @@ static int load_misc_binary(struct linux_binprm *bprm, struct pt_regs *regs)
117 goto _ret; 117 goto _ret;
118 118
119 retval = -ENOEXEC; 119 retval = -ENOEXEC;
120 if (bprm->misc_bang) 120 if (bprm->recursion_depth > BINPRM_MAX_RECURSION)
121 goto _ret; 121 goto _ret;
122 122
123 /* to keep locking time low, we copy the interpreter string */ 123 /* to keep locking time low, we copy the interpreter string */
@@ -197,7 +197,7 @@ static int load_misc_binary(struct linux_binprm *bprm, struct pt_regs *regs)
197 if (retval < 0) 197 if (retval < 0)
198 goto _error; 198 goto _error;
199 199
200 bprm->misc_bang = 1; 200 bprm->recursion_depth++;
201 201
202 retval = search_binary_handler (bprm, regs); 202 retval = search_binary_handler (bprm, regs);
203 if (retval < 0) 203 if (retval < 0)