[PATCH v2] cfg80211: Fix array-bounds warning in fragment copy

[Matthias Kaehlcke]

__ieee80211_amsdu_copy_frag intentionally initializes a pointer to
array[-1] to increment it later to valid values. clang rightfully
generates an array-bounds warning on the initialization statement.

Initialize the pointer to array[0] and change the algorithm from
increment before to increment after consume.

Signed-off-by: Matthias Kaehlcke 
---
Note: Resent to include linux-wireless in cc

 net/wireless/util.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 68e5f2ecee1a..52795ae5337f 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -659,7 +659,7 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
sk_buff *frame,
int offset, int len)
 {
struct skb_shared_info *sh = skb_shinfo(skb);
-   const skb_frag_t *frag = >frags[-1];
+   const skb_frag_t *frag = >frags[0];
struct page *frag_page;
void *frag_ptr;
int frag_len, frag_size;
@@ -672,10 +672,10 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
sk_buff *frame,
 
while (offset >= frag_size) {
offset -= frag_size;
-   frag++;
frag_page = skb_frag_page(frag);
frag_ptr = skb_frag_address(frag);
frag_size = skb_frag_size(frag);
+   frag++;
}
 
frag_ptr += offset;
@@ -687,12 +687,12 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
sk_buff *frame,
len -= cur_len;
 
while (len > 0) {
-   frag++;
frag_len = skb_frag_size(frag);
cur_len = min(len, frag_len);
__frame_add_frag(frame, skb_frag_page(frag),
 skb_frag_address(frag), cur_len, frag_len);
len -= cur_len;
+   frag++;
}
 }
 
-- 
2.12.2.715.g7642488e1d-goog

[PATCH v2] cfg80211: Fix array-bounds warning in fragment copy

[Matthias Kaehlcke]

__ieee80211_amsdu_copy_frag intentionally initializes a pointer to
array[-1] to increment it later to valid values. clang rightfully
generates an array-bounds warning on the initialization statement.

Initialize the pointer to array[0] and change the algorithm from
increment before to increment after consume.

Signed-off-by: Matthias Kaehlcke 
---
Note: Resent to include linux-wireless in cc

 net/wireless/util.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 68e5f2ecee1a..52795ae5337f 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -659,7 +659,7 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
sk_buff *frame,
int offset, int len)
 {
struct skb_shared_info *sh = skb_shinfo(skb);
-   const skb_frag_t *frag = >frags[-1];
+   const skb_frag_t *frag = >frags[0];
struct page *frag_page;
void *frag_ptr;
int frag_len, frag_size;
@@ -672,10 +672,10 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
sk_buff *frame,
 
while (offset >= frag_size) {
offset -= frag_size;
-   frag++;
frag_page = skb_frag_page(frag);
frag_ptr = skb_frag_address(frag);
frag_size = skb_frag_size(frag);
+   frag++;
}
 
frag_ptr += offset;
@@ -687,12 +687,12 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
sk_buff *frame,
len -= cur_len;
 
while (len > 0) {
-   frag++;
frag_len = skb_frag_size(frag);
cur_len = min(len, frag_len);
__frame_add_frag(frame, skb_frag_page(frag),
 skb_frag_address(frag), cur_len, frag_len);
len -= cur_len;
+   frag++;
}
 }
 
-- 
2.12.2.715.g7642488e1d-goog

Re: [PATCH v2] cfg80211: Fix array-bounds warning in fragment copy

[Johannes Berg]

On Mon, 2017-04-10 at 14:36 -0700, Matthias Kaehlcke wrote:
> Ping, any feedback on this patch?

You didn't cc linux-wireless, so it fell through the cracks ... I'll
try to remember it when I merge later.

johannes

Re: [PATCH v2] cfg80211: Fix array-bounds warning in fragment copy

[Johannes Berg]

On Mon, 2017-04-10 at 14:36 -0700, Matthias Kaehlcke wrote:
> Ping, any feedback on this patch?

You didn't cc linux-wireless, so it fell through the cracks ... I'll
try to remember it when I merge later.

johannes

Re: [PATCH v2] cfg80211: Fix array-bounds warning in fragment copy

[Matthias Kaehlcke]

El Mon, Mar 27, 2017 at 12:58:22PM -0700 Matthias Kaehlcke ha dit:

> __ieee80211_amsdu_copy_frag intentionally initializes a pointer to
> array[-1] to increment it later to valid values. clang rightfully
> generates an array-bounds warning on the initialization statement.
> 
> Initialize the pointer to array[0] and change the algorithm from
> increment before to increment after consume.
> 
> Signed-off-by: Matthias Kaehlcke 
> ---
>  net/wireless/util.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/net/wireless/util.c b/net/wireless/util.c
> index 68e5f2ecee1a..52795ae5337f 100644
> --- a/net/wireless/util.c
> +++ b/net/wireless/util.c
> @@ -659,7 +659,7 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
> sk_buff *frame,
>   int offset, int len)
>  {
>   struct skb_shared_info *sh = skb_shinfo(skb);
> - const skb_frag_t *frag = >frags[-1];
> + const skb_frag_t *frag = >frags[0];
>   struct page *frag_page;
>   void *frag_ptr;
>   int frag_len, frag_size;
> @@ -672,10 +672,10 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
> sk_buff *frame,
>  
>   while (offset >= frag_size) {
>   offset -= frag_size;
> - frag++;
>   frag_page = skb_frag_page(frag);
>   frag_ptr = skb_frag_address(frag);
>   frag_size = skb_frag_size(frag);
> + frag++;
>   }
>  
>   frag_ptr += offset;
> @@ -687,12 +687,12 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
> sk_buff *frame,
>   len -= cur_len;
>  
>   while (len > 0) {
> - frag++;
>   frag_len = skb_frag_size(frag);
>   cur_len = min(len, frag_len);
>   __frame_add_frag(frame, skb_frag_page(frag),
>skb_frag_address(frag), cur_len, frag_len);
>   len -= cur_len;
> + frag++;
>   }
>  }
>  

Ping, any feedback on this patch?

Thanks

Matthias

Re: [PATCH v2] cfg80211: Fix array-bounds warning in fragment copy

[Matthias Kaehlcke]

El Mon, Mar 27, 2017 at 12:58:22PM -0700 Matthias Kaehlcke ha dit:

> __ieee80211_amsdu_copy_frag intentionally initializes a pointer to
> array[-1] to increment it later to valid values. clang rightfully
> generates an array-bounds warning on the initialization statement.
> 
> Initialize the pointer to array[0] and change the algorithm from
> increment before to increment after consume.
> 
> Signed-off-by: Matthias Kaehlcke 
> ---
>  net/wireless/util.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/net/wireless/util.c b/net/wireless/util.c
> index 68e5f2ecee1a..52795ae5337f 100644
> --- a/net/wireless/util.c
> +++ b/net/wireless/util.c
> @@ -659,7 +659,7 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
> sk_buff *frame,
>   int offset, int len)
>  {
>   struct skb_shared_info *sh = skb_shinfo(skb);
> - const skb_frag_t *frag = >frags[-1];
> + const skb_frag_t *frag = >frags[0];
>   struct page *frag_page;
>   void *frag_ptr;
>   int frag_len, frag_size;
> @@ -672,10 +672,10 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
> sk_buff *frame,
>  
>   while (offset >= frag_size) {
>   offset -= frag_size;
> - frag++;
>   frag_page = skb_frag_page(frag);
>   frag_ptr = skb_frag_address(frag);
>   frag_size = skb_frag_size(frag);
> + frag++;
>   }
>  
>   frag_ptr += offset;
> @@ -687,12 +687,12 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
> sk_buff *frame,
>   len -= cur_len;
>  
>   while (len > 0) {
> - frag++;
>   frag_len = skb_frag_size(frag);
>   cur_len = min(len, frag_len);
>   __frame_add_frag(frame, skb_frag_page(frag),
>skb_frag_address(frag), cur_len, frag_len);
>   len -= cur_len;
> + frag++;
>   }
>  }
>  

Ping, any feedback on this patch?

Thanks

Matthias

[PATCH v2] cfg80211: Fix array-bounds warning in fragment copy

[Matthias Kaehlcke]

__ieee80211_amsdu_copy_frag intentionally initializes a pointer to
array[-1] to increment it later to valid values. clang rightfully
generates an array-bounds warning on the initialization statement.

Initialize the pointer to array[0] and change the algorithm from
increment before to increment after consume.

Signed-off-by: Matthias Kaehlcke 
---
 net/wireless/util.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 68e5f2ecee1a..52795ae5337f 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -659,7 +659,7 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
sk_buff *frame,
int offset, int len)
 {
struct skb_shared_info *sh = skb_shinfo(skb);
-   const skb_frag_t *frag = >frags[-1];
+   const skb_frag_t *frag = >frags[0];
struct page *frag_page;
void *frag_ptr;
int frag_len, frag_size;
@@ -672,10 +672,10 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
sk_buff *frame,
 
while (offset >= frag_size) {
offset -= frag_size;
-   frag++;
frag_page = skb_frag_page(frag);
frag_ptr = skb_frag_address(frag);
frag_size = skb_frag_size(frag);
+   frag++;
}
 
frag_ptr += offset;
@@ -687,12 +687,12 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
sk_buff *frame,
len -= cur_len;
 
while (len > 0) {
-   frag++;
frag_len = skb_frag_size(frag);
cur_len = min(len, frag_len);
__frame_add_frag(frame, skb_frag_page(frag),
 skb_frag_address(frag), cur_len, frag_len);
len -= cur_len;
+   frag++;
}
 }
 
-- 
2.12.1.578.ge9c3154ca4-goog

[PATCH v2] cfg80211: Fix array-bounds warning in fragment copy

[Matthias Kaehlcke]

__ieee80211_amsdu_copy_frag intentionally initializes a pointer to
array[-1] to increment it later to valid values. clang rightfully
generates an array-bounds warning on the initialization statement.

Initialize the pointer to array[0] and change the algorithm from
increment before to increment after consume.

Signed-off-by: Matthias Kaehlcke 
---
 net/wireless/util.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 68e5f2ecee1a..52795ae5337f 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -659,7 +659,7 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
sk_buff *frame,
int offset, int len)
 {
struct skb_shared_info *sh = skb_shinfo(skb);
-   const skb_frag_t *frag = >frags[-1];
+   const skb_frag_t *frag = >frags[0];
struct page *frag_page;
void *frag_ptr;
int frag_len, frag_size;
@@ -672,10 +672,10 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
sk_buff *frame,
 
while (offset >= frag_size) {
offset -= frag_size;
-   frag++;
frag_page = skb_frag_page(frag);
frag_ptr = skb_frag_address(frag);
frag_size = skb_frag_size(frag);
+   frag++;
}
 
frag_ptr += offset;
@@ -687,12 +687,12 @@ __ieee80211_amsdu_copy_frag(struct sk_buff *skb, struct 
sk_buff *frame,
len -= cur_len;
 
while (len > 0) {
-   frag++;
frag_len = skb_frag_size(frag);
cur_len = min(len, frag_len);
__frame_add_frag(frame, skb_frag_page(frag),
 skb_frag_address(frag), cur_len, frag_len);
len -= cur_len;
+   frag++;
}
 }
 
-- 
2.12.1.578.ge9c3154ca4-goog