Commit 91219352 authored by Tetsuo Handa's avatar Tetsuo Handa Committed by Linus Torvalds

exec: do not call request_module() twice from search_binary_handler()

Currently, search_binary_handler() tries to load binary loader module
using request_module() if a loader for the requested program is not yet
loaded.  But second attempt of request_module() does not affect the result
of search_binary_handler().

If request_module() triggered recursion, calling request_module() twice
causes 2 to the power of MAX_KMOD_CONCURRENT (= 50) repetitions.  It is
not an infinite loop but is sufficient for users to consider as a hang up.

Therefore, this patch changes not to call request_module() twice, making 1
to the power of MAX_KMOD_CONCURRENT repetitions in case of recursion.
Signed-off-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: default avatarRichard Weinberger <richard@nod.at>
Tested-by: default avatarRichard Weinberger <richard@nod.at>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent aacb3d17
...@@ -1440,6 +1440,8 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) ...@@ -1440,6 +1440,8 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
printable(bprm->buf[2]) && printable(bprm->buf[2]) &&
printable(bprm->buf[3])) printable(bprm->buf[3]))
break; /* -ENOEXEC */ break; /* -ENOEXEC */
if (try)
break; /* -ENOEXEC */
request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
#endif #endif
} }
......
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