[PATCH] fs/nfs: fix covscan error: FORWARD

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* [PATCH] fs/nfs: fix covscan error: FORWARD_NULL
@ 2017-05-05 10:26 Jianhong.Yin
       [not found] ` <b100e3a6-c59b-9729-7129-6c7ca163dacf@Netapp.com>
  0 siblings, 1 reply; 3+ messages in thread
From: Jianhong.Yin @ 2017-05-05 10:26 UTC (permalink / raw)
  To: linux-nfs; +Cc: trond.myklebust, bfields, steved, Jianhong.Yin

From: "Jianhong.Yin" <yin-jianhong@163.com>

fs/nfs/nfs4xdr.c: encode_attrs()
'''
Error: FORWARD_NULL (CWE-476): [#def3702]
.../fs/nfs/nfs4xdr.c:1085: var_compare_op: Comparing "label" to null implies that "label" might be null.
.../fs/nfs/nfs4xdr.c:1129: var_deref_op: Dereferencing null pointer "label".
 1127|   	}
 1128|   	if (bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
 1129|-> 		*p++ = cpu_to_be32(label->lfs);
 1130|   		*p++ = cpu_to_be32(label->pi);
 1131|   		*p++ = cpu_to_be32(label->len);

Error: FORWARD_NULL (CWE-476): [#def3703]
.../fs/nfs/nfs4xdr.c:1027: var_compare_op: Comparing "umask" to null implies that "umask" might be null.
.../fs/nfs/nfs4xdr.c:1136: var_deref_op: Dereferencing null pointer "umask".
 1134|   	if (bmval[2] & FATTR4_WORD2_MODE_UMASK) {
 1135|   		*p++ = cpu_to_be32(iap->ia_mode & S_IALLUGO);
 1136|-> 		*p++ = cpu_to_be32(*umask);
 1137|   	}
'''

Signed-off-by: Jianhong Yin <yin-jianhong@163.com>
---
 fs/nfs/nfs4xdr.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 80ce289..a86ed66 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1124,7 +1124,7 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
 		} else
 			*p++ = cpu_to_be32(NFS4_SET_TO_SERVER_TIME);
 	}
-	if (bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
+	if (label && bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
 		*p++ = cpu_to_be32(label->lfs);
 		*p++ = cpu_to_be32(label->pi);
 		*p++ = cpu_to_be32(label->len);
@@ -1132,7 +1132,8 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
 	}
 	if (bmval[2] & FATTR4_WORD2_MODE_UMASK) {
 		*p++ = cpu_to_be32(iap->ia_mode & S_IALLUGO);
-		*p++ = cpu_to_be32(*umask);
+		if (umask != NULL)
+			*p++ = cpu_to_be32(*umask);
 	}
 
 /* out: */
-- 
1.8.3.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

[parent not found: <b100e3a6-c59b-9729-7129-6c7ca163dacf@Netapp.com>]

* Re: [PATCH] fs/nfs: fix covscan error: FORWARD_NULL
       [not found] ` <b100e3a6-c59b-9729-7129-6c7ca163dacf@Netapp.com>
@ 2017-05-06  7:42   ` Jianhong Yin
  0 siblings, 0 replies; 3+ messages in thread
From: Jianhong Yin @ 2017-05-06  7:42 UTC (permalink / raw)
  To: Anna Schumaker; +Cc: linux-nfs, trond myklebust, bfields, steved


----- 原始邮件 -----
> 发件人: "Anna Schumaker" <Anna.Schumaker@Netapp.com>
> 收件人: "Jianhong.Yin" <jiyin@redhat.com>, linux-nfs@vger.kernel.org
> 抄送: "trond myklebust" <trond.myklebust@primarydata.com>, bfields@redhat.com, steved@redhat.com, "Jianhong.Yin"
> <yin-jianhong@163.com>
> 发送时间: 星期六, 2017年 5 月 06日 上午 1:52:35
> 主题: Re: [PATCH] fs/nfs: fix covscan error: FORWARD_NULL
> 
> Hi Jianhong,
> 
> On 05/05/2017 06:26 AM, Jianhong.Yin wrote:
> > From: "Jianhong.Yin" <yin-jianhong@163.com>
> > 
> > fs/nfs/nfs4xdr.c: encode_attrs()
> > '''
> > Error: FORWARD_NULL (CWE-476): [#def3702]
> > .../fs/nfs/nfs4xdr.c:1085: var_compare_op: Comparing "label" to null
> > implies that "label" might be null.
> > .../fs/nfs/nfs4xdr.c:1129: var_deref_op: Dereferencing null pointer
> > "label".
> >  1127|   	}
> >  1128|   	if (bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
> >  1129|-> 		*p++ = cpu_to_be32(label->lfs);
> >  1130|   		*p++ = cpu_to_be32(label->pi);
> >  1131|   		*p++ = cpu_to_be32(label->len);
> > 
> > Error: FORWARD_NULL (CWE-476): [#def3703]
> > .../fs/nfs/nfs4xdr.c:1027: var_compare_op: Comparing "umask" to null
> > implies that "umask" might be null.
> > .../fs/nfs/nfs4xdr.c:1136: var_deref_op: Dereferencing null pointer
> > "umask".
> >  1134|   	if (bmval[2] & FATTR4_WORD2_MODE_UMASK) {
> >  1135|   		*p++ = cpu_to_be32(iap->ia_mode & S_IALLUGO);
> >  1136|-> 		*p++ = cpu_to_be32(*umask);
> >  1137|   	}
> > '''
> > 
> > Signed-off-by: Jianhong Yin <yin-jianhong@163.com>
> > ---
> >  fs/nfs/nfs4xdr.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> > 
> > diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
> > index 80ce289..a86ed66 100644
> > --- a/fs/nfs/nfs4xdr.c
> > +++ b/fs/nfs/nfs4xdr.c
> > @@ -1124,7 +1124,7 @@ static void encode_attrs(struct xdr_stream *xdr,
> > const struct iattr *iap,
> >  		} else
> >  			*p++ = cpu_to_be32(NFS4_SET_TO_SERVER_TIME);
> >  	}
> > -	if (bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
> > +	if (label && bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
> 
> As far as I can tell, the FATTR4_WORD2_SECURITY_LABEL flag is only set if
> label exists, and the same goes for the FATTR4_WORD2_MODE_UMASK flag below.
> This means that it's not possible to have a null pointer dereference in
> these sections of code.  Is there a way to mark this as a false positive in
> your covscan tool?

Hi Anna

 Yes, you are right. this patch is unnecessary. just let code *looks* more safe.

 "covscan" means the coverity scan(a "Static Analysis" tool).
   lots of it's warning/error need to be marked as false positive.
 thank you for correcting me

Jianhong

> 
> Thanks,
> Anna
> 
> >  		*p++ = cpu_to_be32(label->lfs);
> >  		*p++ = cpu_to_be32(label->pi);
> >  		*p++ = cpu_to_be32(label->len);
> > @@ -1132,7 +1132,8 @@ static void encode_attrs(struct xdr_stream *xdr,
> > const struct iattr *iap,
> >  	}
> >  	if (bmval[2] & FATTR4_WORD2_MODE_UMASK) {
> >  		*p++ = cpu_to_be32(iap->ia_mode & S_IALLUGO);
> > -		*p++ = cpu_to_be32(*umask);
> > +		if (umask != NULL)
> > +			*p++ = cpu_to_be32(*umask);
> >  	}
> >  
> >  /* out: */
> > 
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread

* [PATCH] fs/nfs: fix covscan error: FORWARD_NULL
@ 2017-05-05  3:58 Jianhong.Yin
  0 siblings, 0 replies; 3+ messages in thread
From: Jianhong.Yin @ 2017-05-05  3:58 UTC (permalink / raw)
  To: linux-nfs; +Cc: Trond.Myklebust, bfields, steved, Jianhong.Yin

'''
Error: FORWARD_NULL (CWE-476): [#def3702]
.../fs/nfs/nfs4xdr.c:1085: var_compare_op: Comparing "label" to null implies that "label" might be null.
.../fs/nfs/nfs4xdr.c:1129: var_deref_op: Dereferencing null pointer "label".
 1127|   	}
 1128|   	if (bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
 1129|-> 		*p++ = cpu_to_be32(label->lfs);
 1130|   		*p++ = cpu_to_be32(label->pi);
 1131|   		*p++ = cpu_to_be32(label->len);

Error: FORWARD_NULL (CWE-476): [#def3703]
.../fs/nfs/nfs4xdr.c:1027: var_compare_op: Comparing "umask" to null implies that "umask" might be null.
.../fs/nfs/nfs4xdr.c:1136: var_deref_op: Dereferencing null pointer "umask".
 1134|   	if (bmval[2] & FATTR4_WORD2_MODE_UMASK) {
 1135|   		*p++ = cpu_to_be32(iap->ia_mode & S_IALLUGO);
 1136|-> 		*p++ = cpu_to_be32(*umask);
 1137|   	}
'''

Signed-off-by: Jianhong Yin <yin-jianhong@163.com>
---
 fs/nfs/nfs4xdr.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 80ce289..a86ed66 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1124,7 +1124,7 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
 		} else
 			*p++ = cpu_to_be32(NFS4_SET_TO_SERVER_TIME);
 	}
-	if (bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
+	if (label && bmval[2] & FATTR4_WORD2_SECURITY_LABEL) {
 		*p++ = cpu_to_be32(label->lfs);
 		*p++ = cpu_to_be32(label->pi);
 		*p++ = cpu_to_be32(label->len);
@@ -1132,7 +1132,8 @@ static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
 	}
 	if (bmval[2] & FATTR4_WORD2_MODE_UMASK) {
 		*p++ = cpu_to_be32(iap->ia_mode & S_IALLUGO);
-		*p++ = cpu_to_be32(*umask);
+		if (umask != NULL)
+			*p++ = cpu_to_be32(*umask);
 	}
 
 /* out: */
-- 
1.8.3.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

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2017-05-05 10:26 [PATCH] fs/nfs: fix covscan error: FORWARD_NULL Jianhong.Yin
     [not found] ` <b100e3a6-c59b-9729-7129-6c7ca163dacf@Netapp.com>
2017-05-06  7:42   ` Jianhong Yin
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