Messages in this thread Patch in this message | | | Date | Mon, 9 May 2011 22:09:19 +0200 (CEST) | From | Jesper Juhl <> | Subject | Re: [Stable-review] [patch 31/38] ARM: 6891/1: prevent heap corruption in OABI semtimedop |
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On Sat, 7 May 2011, Ben Hutchings wrote:
> On Thu, 2011-05-05 at 17:11 -0700, Greg KH wrote: > > 2.6.38-stable review patch. If anyone has any objections, please let us know. > > > > ------------------ > > > > From: Dan Rosenberg <drosenberg@vsecurity.com> > > > > commit 0f22072ab50cac7983f9660d33974b45184da4f9 upstream. > > > > When CONFIG_OABI_COMPAT is set, the wrapper for semtimedop does not > > bound the nsops argument. A sufficiently large value will cause an > > integer overflow in allocation size, followed by copying too much data > > into the allocated buffer. Fix this by restricting nsops to SEMOPM. > > Untested. > > > > Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> > > Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> > > Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> > > > > --- > > arch/arm/kernel/sys_oabi-compat.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > --- a/arch/arm/kernel/sys_oabi-compat.c > > +++ b/arch/arm/kernel/sys_oabi-compat.c > > @@ -311,7 +311,7 @@ asmlinkage long sys_oabi_semtimedop(int > > long err; > > int i; > > > > - if (nsops < 1) > > + if (nsops < 1 || nsops > SEMOPM) > > return -EINVAL; > > It's not that important, but the manual page says the error code should > E2BIG in the latter case. >
So something like this...
Return correct error (E2BIG) when nsops is greater than SEMOPM in sys_oabi_semtimedop. The man page (semtimedop(2)) lists this as the proper error in ths case: "E2BIG The argument nsops is greater than SEMOPM, the maximum number of operations allowed per system call."
Signed-off-by: Jesper Juhl <jj@chaosbits.net> Reported-by: Ben Hutchings <ben@decadent.org.uk> -- sys_oabi-compat.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/arm/kernel/sys_oabi-compat.c b/arch/arm/kernel/sys_oabi-compat.c index af0aaeb..c196ad7 100644 --- a/arch/arm/kernel/sys_oabi-compat.c +++ b/arch/arm/kernel/sys_oabi-compat.c @@ -311,8 +311,10 @@ asmlinkage long sys_oabi_semtimedop(int semid, long err; int i; - if (nsops < 1 || nsops > SEMOPM) + if (nsops < 1) return -EINVAL; + else if (nsops > SEMOPM) + return -E2BIG; sops = kmalloc(sizeof(*sops) * nsops, GFP_KERNEL); if (!sops) return -ENOMEM;
-- Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/ Don't top-post http://www.catb.org/jargon/html/T/top-post.html Plain text mails only, please.
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