irda information disclosure: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-4529
From: Dan Rosenberg <[email protected]> Date: Wed, 22 Dec 2010 13:58:27 +0000 Subject: [PATCH] irda: prevent integer underflow in IRLMP_ENUMDEVICES
commit fdac1e0697356ac212259f2147aa60c72e334861 upstream. If the user-provided len is less than the expected offset, the IRLMP_ENUMDEVICES getsockopt will do a copy_to_user() with a very large size value. While this isn't be a security issue on x86 because it will get caught by the access_ok() check, it may leak large amounts of kernel heap on other architectures. In any event, this patch fixes it. Signed-off-by: Dan Rosenberg <[email protected]> Signed-off-by: David S. Miller <[email protected]> [dannf: Backport to 2.6.32] --- --- a/net/irda/af_irda.c +++ b/net/irda/af_irda.c @@ -2164,6 +2164,14 @@ static int irda_getsockopt(struct socket switch (optname) { case IRLMP_ENUMDEVICES: + + /* Offset to first device entry */ + offset = sizeof(struct irda_device_list) - + sizeof(struct irda_device_info); + + if (len < offset) + return -EINVAL; + /* Ask lmp for the current discovery log */ discoveries = irlmp_get_discoveries(&list.len, self->mask.word, self->nslots); @@ -2173,15 +2181,9 @@ static int irda_getsockopt(struct socket err = 0; /* Write total list length back to client */ - if (copy_to_user(optval, &list, - sizeof(struct irda_device_list) - - sizeof(struct irda_device_info))) + if (copy_to_user(optval, &list, offset)) err = -EFAULT; - /* Offset to first device entry */ - offset = sizeof(struct irda_device_list) - - sizeof(struct irda_device_info); - /* Copy the list itself - watch for overflow */ if(list.len > 2048) {
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