[libvirt] [PATCH] util: Fix leak in virStringTrimOptionalNewline

Martin Kletzander posted 1 patch 6 years, 4 months ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/libvirt tags/patchew/2c81dee1fb447aa3fa3e1298a2ad638fed4e9010.1511384630.git.mkletzan@redhat.com
src/util/virstring.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
[libvirt] [PATCH] util: Fix leak in virStringTrimOptionalNewline
Posted by Martin Kletzander 6 years, 4 months ago
Do not access any data if strlen() == 0.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
---
 src/util/virstring.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/util/virstring.c b/src/util/virstring.c
index eac4774b533e..b2ebce27ff49 100644
--- a/src/util/virstring.c
+++ b/src/util/virstring.c
@@ -1394,9 +1394,13 @@ virStringEncodeBase64(const uint8_t *buf, size_t buflen)
  */
 void virStringTrimOptionalNewline(char *str)
 {
-    char *tmp = str + strlen(str) - 1;
-    if (*tmp == '\n')
-        *tmp = '\0';
+    size_t len = strlen(str);
+
+    if (!len)
+        return;
+
+    if (str[len - 1] == '\n')
+        str[len - 1] = '\0';
 }
 
 
-- 
2.15.0

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Re: [libvirt] [PATCH] util: Fix leak in virStringTrimOptionalNewline
Posted by Michal Privoznik 6 years, 4 months ago
On 11/22/2017 10:03 PM, Martin Kletzander wrote:
> Do not access any data if strlen() == 0.
> 
> Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
> ---
>  src/util/virstring.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/src/util/virstring.c b/src/util/virstring.c
> index eac4774b533e..b2ebce27ff49 100644
> --- a/src/util/virstring.c
> +++ b/src/util/virstring.c
> @@ -1394,9 +1394,13 @@ virStringEncodeBase64(const uint8_t *buf, size_t buflen)
>   */
>  void virStringTrimOptionalNewline(char *str)
>  {
> -    char *tmp = str + strlen(str) - 1;
> -    if (*tmp == '\n')
> -        *tmp = '\0';
> +    size_t len = strlen(str);
> +
> +    if (!len)
> +        return;
> +
> +    if (str[len - 1] == '\n')
> +        str[len - 1] = '\0';
>  }
>  
>  
> 

/me wonders if we need this function to accept NULL. Looking at the
callers we don't just yet.

ACK

Michal

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