From: Michal Kubecek <mkubecek@xxxxxxx> 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 12e3594698f6c3ab6ebacc79f2fb2ad2bb5952b5 upstream. In ipcomp_compress(), sortirq is enabled too early, allowing the per-cpu scratch buffer to be rewritten by ipcomp_decompress() (called on the same CPU in softirq context) between populating the buffer and copying the compressed data to the skb. v2: as pointed out by Steffen Klassert, if we also move the local_bh_disable() before reading the per-cpu pointers, we can get rid of get_cpu()/put_cpu(). v3: removed ipcomp_decompress part (as explained by Herbert Xu, it cannot be called from process context), get rid of cpu variable (thanks to Eric Dumazet) Signed-off-by: Michal Kubecek <mkubecek@xxxxxxx> Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx> Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- net/xfrm/xfrm_ipcomp.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c index 2906d520eea7..3be02b680268 100644 --- a/net/xfrm/xfrm_ipcomp.c +++ b/net/xfrm/xfrm_ipcomp.c @@ -141,14 +141,14 @@ static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb) const int plen = skb->len; int dlen = IPCOMP_SCRATCH_SIZE; u8 *start = skb->data; - const int cpu = get_cpu(); - u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu); - struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu); + struct crypto_comp *tfm; + u8 *scratch; int err; local_bh_disable(); + scratch = *this_cpu_ptr(ipcomp_scratches); + tfm = *this_cpu_ptr(ipcd->tfms); err = crypto_comp_compress(tfm, start, plen, scratch, &dlen); - local_bh_enable(); if (err) goto out; @@ -158,13 +158,13 @@ static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb) } memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen); - put_cpu(); + local_bh_enable(); pskb_trim(skb, dlen + sizeof(struct ip_comp_hdr)); return 0; out: - put_cpu(); + local_bh_enable(); return err; } -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html