Re: [PATCH 3.12 117/133] alpha: fix broken network checksum
On Thu, 6 Feb 2014, Michael Cree wrote: > On Tue, Feb 04, 2014 at 01:08:38PM -0800, Greg Kroah-Hartman wrote: > > 3.12-stable review patch. If anyone has any objections, please let me know. > > > > -- > > > > From: Mikulas Patocka > > > > commit 0ef38d70d4118b2ce1a538d14357be5ff9dc2bbd upstream. > > > > The patch 3ddc5b46a8e90f3c9251338b60191d0a804b0d92 breaks networking on > > alpha (there is a follow-up fix 5cfe8f1ba5eebe6f4b6e5858cdb1a5be4f3272a6, > > but networking is still broken even with the second patch). > > I wonder whether that follow-up (partial) fix mentioned > (5cfe8f1ba5eebe6f4b6e5858cdb1a5be4f3272a6) should be pulled into 3.12 stable > too? > > Cheers > Michael. I think it doesn't have to be backported. Mikulas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 3.12 117/133] alpha: fix broken network checksum
On Thu, 6 Feb 2014, Michael Cree wrote: > On Tue, Feb 04, 2014 at 01:08:38PM -0800, Greg Kroah-Hartman wrote: > > 3.12-stable review patch. If anyone has any objections, please let me know. > > > > -- > > > > From: Mikulas Patocka > > > > commit 0ef38d70d4118b2ce1a538d14357be5ff9dc2bbd upstream. > > > > The patch 3ddc5b46a8e90f3c9251338b60191d0a804b0d92 breaks networking on > > alpha (there is a follow-up fix 5cfe8f1ba5eebe6f4b6e5858cdb1a5be4f3272a6, > > but networking is still broken even with the second patch). > > I wonder whether that follow-up (partial) fix mentioned > (5cfe8f1ba5eebe6f4b6e5858cdb1a5be4f3272a6) should be pulled into 3.12 stable > too? > > Cheers > Michael. Hi It is quite confusing - csum_partial_copy_from_user is only called from csum_and_copy_from_user in include/net/checksum.h. csum_and_copy_from_user already verifies the source memory range with access_ok. Despite this, people started to add access_ok to many architecture-specific versions of csum_partial_copy_from_user (for example 3ddc5b46a8e90f3c9251338b60191d0a804b0d92). It seems that the best thing is to revert 0ef38d70d4118b2ce1a538d14357be5ff9dc2bbd, 5cfe8f1ba5eebe6f4b6e5858cdb1a5be4f3272a6 and csum_partial_copy_from_user change from 3ddc5b46a8e90f3c9251338b60191d0a804b0d92. David, you are maintainer of networking - does it have any deeper sense to perform access_ok in csum_partial_copy_from_user if the caller performs this check already? Should this be just removed? Also - the x86 and alpha implementation of csum_and_copy_from_user zero the destination buffer on userspace-access error - but csum_and_copy_from_user (that calls these function) doesn't zero the destination buffer on error. Should the destination buffer be zeroed on error or not? Mikulas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 3.12 117/133] alpha: fix broken network checksum
On Tue, Feb 04, 2014 at 01:08:38PM -0800, Greg Kroah-Hartman wrote: > 3.12-stable review patch. If anyone has any objections, please let me know. > > -- > > From: Mikulas Patocka > > commit 0ef38d70d4118b2ce1a538d14357be5ff9dc2bbd upstream. > > The patch 3ddc5b46a8e90f3c9251338b60191d0a804b0d92 breaks networking on > alpha (there is a follow-up fix 5cfe8f1ba5eebe6f4b6e5858cdb1a5be4f3272a6, > but networking is still broken even with the second patch). I wonder whether that follow-up (partial) fix mentioned (5cfe8f1ba5eebe6f4b6e5858cdb1a5be4f3272a6) should be pulled into 3.12 stable too? Cheers Michael. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 3.12 117/133] alpha: fix broken network checksum
3.12-stable review patch. If anyone has any objections, please let me know.
--
From: Mikulas Patocka
commit 0ef38d70d4118b2ce1a538d14357be5ff9dc2bbd upstream.
The patch 3ddc5b46a8e90f3c9251338b60191d0a804b0d92 breaks networking on
alpha (there is a follow-up fix 5cfe8f1ba5eebe6f4b6e5858cdb1a5be4f3272a6,
but networking is still broken even with the second patch).
The patch 3ddc5b46a8e90f3c9251338b60191d0a804b0d92 makes
csum_partial_copy_from_user check the pointer with access_ok. However,
csum_partial_copy_from_user is called also from csum_partial_copy_nocheck
and csum_partial_copy_nocheck is called on kernel pointers and it is
supposed not to check pointer validity.
This bug results in ssh session hangs if the system is loaded and bulk
data are printed to ssh terminal.
This patch fixes csum_partial_copy_nocheck to call set_fs(KERNEL_DS), so
that access_ok in csum_partial_copy_from_user accepts kernel-space
addresses.
Signed-off-by: Mikulas Patocka
Signed-off-by: Matt Turner
Signed-off-by: Greg Kroah-Hartman
---
arch/alpha/lib/csum_partial_copy.c |9 +++--
1 file changed, 7 insertions(+), 2 deletions(-)
--- a/arch/alpha/lib/csum_partial_copy.c
+++ b/arch/alpha/lib/csum_partial_copy.c
@@ -378,6 +378,11 @@ csum_partial_copy_from_user(const void _
__wsum
csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
{
- return csum_partial_copy_from_user((__force const void __user *)src,
- dst, len, sum, NULL);
+ __wsum checksum;
+ mm_segment_t oldfs = get_fs();
+ set_fs(KERNEL_DS);
+ checksum = csum_partial_copy_from_user((__force const void __user *)src,
+ dst, len, sum, NULL);
+ set_fs(oldfs);
+ return checksum;
}
--
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