path: root/arch
diff options
authorMikulas Patocka <>2014-01-22 23:04:33 -0500
committerMatt Turner <>2014-01-31 09:21:55 -0800
commit0ef38d70d4118b2ce1a538d14357be5ff9dc2bbd (patch)
treeb44ba96de2442da88519a6d4ff5c00cd48afd032 /arch
parenta9302e8439445710552886e7b623dbcfa943a1f2 (diff)
alpha: fix broken network checksum
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. Cc: Signed-off-by: Mikulas Patocka <> Signed-off-by: Matt Turner <>
Diffstat (limited to 'arch')
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/alpha/lib/csum_partial_copy.c b/arch/alpha/lib/csum_partial_copy.c
index ff3c10721caf..5675dca8dbb1 100644
--- 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 __user *src, void *dst, int len,
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;