From: Colin Ian King <[email protected]>
The rol32 call is currently rotating hash but the rol'd value is
being discarded. I believe the current code is incorrect and hash
should be assigned the rotated value returned from rol32.
Detected by CoverityScan, CID#1468411 ("Useless call")
Fixes: b5facfdba14c ("ipv6: sr: Compute flowlabel for outer IPv6 header of seg6 encap mode")
Signed-off-by: Colin Ian King <[email protected]>
---
net/ipv6/seg6_iptunnel.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c
index 19ccf0dc996c..a8854dd3e9c5 100644
--- a/net/ipv6/seg6_iptunnel.c
+++ b/net/ipv6/seg6_iptunnel.c
@@ -101,7 +101,7 @@ static __be32 seg6_make_flowlabel(struct net *net, struct sk_buff *skb,
if (do_flowlabel > 0) {
hash = skb_get_hash(skb);
- rol32(hash, 16);
+ hash = rol32(hash, 16);
flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;
} else if (!do_flowlabel && skb->protocol == htons(ETH_P_IPV6)) {
flowlabel = ip6_flowlabel(inner_hdr);
--
2.17.1
On 07/17/2018 04:52 PM, Colin King wrote:
> From: Colin Ian King<[email protected]>
>
> The rol32 call is currently rotating hash but the rol'd value is
> being discarded. I believe the current code is incorrect and hash
> should be assigned the rotated value returned from rol32.
>
> Detected by CoverityScan, CID#1468411 ("Useless call")
>
> Fixes: b5facfdba14c ("ipv6: sr: Compute flowlabel for outer IPv6 header of seg6 encap mode")
> Signed-off-by: Colin Ian King<[email protected]>
Acked-by: [email protected]
Good catch, thanks !
In that case, the same issue is present in
include/net/ipv6.h:ip6_make_flowlabel().
On Tue, 2018-07-17 at 17:03 +0100, David Lebrun wrote:
> On 07/17/2018 04:52 PM, Colin King wrote:
> > From: Colin Ian King<[email protected]>
> >
> > The rol32 call is currently rotating hash but the rol'd value is
> > being discarded. I believe the current code is incorrect and hash
> > should be assigned the rotated value returned from rol32.
> >
> > Detected by CoverityScan, CID#1468411 ("Useless call")
> >
> > Fixes: b5facfdba14c ("ipv6: sr: Compute flowlabel for outer IPv6 header of seg6 encap mode")
> > Signed-off-by: Colin Ian King<[email protected]>
>
> Acked-by: [email protected]
>
> Good catch, thanks !
>
> In that case, the same issue is present in
> include/net/ipv6.h:ip6_make_flowlabel().
Perhaps all of the ror and rol definitions should add
__must_check
Something like the below and perhaps many more of the
functions that return some value should have __must_chedk
added as well.
---
include/linux/bitops.h | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index af419012d77d..3cddde65c8bb 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -67,7 +67,7 @@ static inline __u64 rol64(__u64 word, unsigned int shift)
* @word: value to rotate
* @shift: bits to roll
*/
-static inline __u64 ror64(__u64 word, unsigned int shift)
+static inline __must_check __u64 ror64(__u64 word, unsigned int shift)
{
return (word >> shift) | (word << (64 - shift));
}
@@ -77,7 +77,7 @@ static inline __u64 ror64(__u64 word, unsigned int shift)
* @word: value to rotate
* @shift: bits to roll
*/
-static inline __u32 rol32(__u32 word, unsigned int shift)
+static inline __must_check __u32 rol32(__u32 word, unsigned int shift)
{
return (word << shift) | (word >> ((-shift) & 31));
}
@@ -87,7 +87,7 @@ static inline __u32 rol32(__u32 word, unsigned int shift)
* @word: value to rotate
* @shift: bits to roll
*/
-static inline __u32 ror32(__u32 word, unsigned int shift)
+static inline __must_check __u32 ror32(__u32 word, unsigned int shift)
{
return (word >> shift) | (word << (32 - shift));
}
@@ -97,7 +97,7 @@ static inline __u32 ror32(__u32 word, unsigned int shift)
* @word: value to rotate
* @shift: bits to roll
*/
-static inline __u16 rol16(__u16 word, unsigned int shift)
+static inline __must_check __u16 rol16(__u16 word, unsigned int shift)
{
return (word << shift) | (word >> (16 - shift));
}
@@ -107,7 +107,7 @@ static inline __u16 rol16(__u16 word, unsigned int shift)
* @word: value to rotate
* @shift: bits to roll
*/
-static inline __u16 ror16(__u16 word, unsigned int shift)
+static inline __must_check __u16 ror16(__u16 word, unsigned int shift)
{
return (word >> shift) | (word << (16 - shift));
}
@@ -117,7 +117,7 @@ static inline __u16 ror16(__u16 word, unsigned int shift)
* @word: value to rotate
* @shift: bits to roll
*/
-static inline __u8 rol8(__u8 word, unsigned int shift)
+static inline __must_check __u8 rol8(__u8 word, unsigned int shift)
{
return (word << shift) | (word >> (8 - shift));
}
@@ -127,7 +127,7 @@ static inline __u8 rol8(__u8 word, unsigned int shift)
* @word: value to rotate
* @shift: bits to roll
*/
-static inline __u8 ror8(__u8 word, unsigned int shift)
+static inline __must_check __u8 ror8(__u8 word, unsigned int shift)
{
return (word >> shift) | (word << (8 - shift));
}
@@ -139,7 +139,7 @@ static inline __u8 ror8(__u8 word, unsigned int shift)
*
* This is safe to use for 16- and 8-bit types as well.
*/
-static inline __s32 sign_extend32(__u32 value, int index)
+static inline __must_check __s32 sign_extend32(__u32 value, int index)
{
__u8 shift = 31 - index;
return (__s32)(value << shift) >> shift;
@@ -150,7 +150,7 @@ static inline __s32 sign_extend32(__u32 value, int index)
* @value: value to sign extend
* @index: 0 based bit index (0<=index<64) to sign bit
*/
-static inline __s64 sign_extend64(__u64 value, int index)
+static inline __must_check __s64 sign_extend64(__u64 value, int index)
{
__u8 shift = 63 - index;
return (__s64)(value << shift) >> shift;
From: Colin King <[email protected]>
Date: Tue, 17 Jul 2018 16:52:54 +0100
> From: Colin Ian King <[email protected]>
>
> The rol32 call is currently rotating hash but the rol'd value is
> being discarded. I believe the current code is incorrect and hash
> should be assigned the rotated value returned from rol32.
>
> Detected by CoverityScan, CID#1468411 ("Useless call")
>
> Fixes: b5facfdba14c ("ipv6: sr: Compute flowlabel for outer IPv6 header of seg6 encap mode")
> Signed-off-by: Colin Ian King <[email protected]>
Applied and queued up for -stable.