[arptables PATCH 0/3] Some minor fixes

[arptables PATCH 0/3] Some minor fixes

[Phil Sutter]

These are some patches I found while cleaning up the attic. They add a
gitignore file, fix for a compiler warning and simplify code in libarptc
a bit.

Phil Sutter (3):
  Add .gitignore
  Eliminate compiler warning about size passed to strncmp()
  libarptc: Simplify alloc_handle by using calloc()

 .gitignore               |  4 ++++
 arptables.c              |  3 +--
 libarptc/libarptc_incl.c | 11 +++--------
 3 files changed, 8 insertions(+), 10 deletions(-)
 create mode 100644 .gitignore

-- 
2.24.0

[arptables PATCH 1/3] Add .gitignore

[Phil Sutter]

Ignore temporary files, created arptables-legacy binary and any present
tags file.

Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 .gitignore | 4 ++++
 1 file changed, 4 insertions(+)
 create mode 100644 .gitignore

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000000000..b2ea4a177d410
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,4 @@
+*.a
+*.o
+/arptables-legacy
+/tags
-- 
2.24.0

[arptables PATCH 2/3] Eliminate compiler warning about size passed to strncmp()

[Phil Sutter]

Gcc complains about the size being equal to destination size, despite
the nul character being explicitly set in following line.

Reduce size by one to make gcc happy. While being at it, drop the
explicit nul character assignment - it is not needed as the buffer was
allocated by calloc().

Fixes: 8f586939999e0 ("fix potential buffer overflows reported by static analysis")
Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 arptables.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arptables.c b/arptables.c
index 09c9ca25217d0..2b6618c2511ef 100644
--- a/arptables.c
+++ b/arptables.c
@@ -2065,8 +2065,7 @@ int do_command(int argc, char *argv[], char **table, arptc_handle_t *handle)
 
 				target->t = fw_calloc(1, size);
 				target->t->u.target_size = size;
-				strncpy(target->t->u.user.name, jumpto, sizeof(target->t->u.user.name));
-				target->t->u.user.name[sizeof(target->t->u.user.name)-1] = '\0';
+				strncpy(target->t->u.user.name, jumpto, sizeof(target->t->u.user.name) - 1);
 				target->t->u.user.revision = target->revision;
 /*
 				target->init(target->t, &fw.nfcache);
-- 
2.24.0

[arptables PATCH 3/3] libarptc: Simplify alloc_handle by using calloc()

[Phil Sutter]

No need to explicitly set fields to zero when using calloc().

Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 libarptc/libarptc_incl.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/libarptc/libarptc_incl.c b/libarptc/libarptc_incl.c
index ca23da6474990..c4d5de3f39a15 100644
--- a/libarptc/libarptc_incl.c
+++ b/libarptc/libarptc_incl.c
@@ -191,21 +191,16 @@ alloc_handle(const char *tablename, unsigned int size, unsigned int num_rules)
 		+ size
 		+ num_rules * sizeof(struct counter_map);
 
-	if ((h = malloc(len)) == NULL) {
+	if ((h = calloc(1, len)) == NULL) {
 		errno = ENOMEM;
 		return NULL;
 	}
 
-	h->changed = 0;
-	h->cache_num_chains = 0;
-	h->cache_chain_heads = NULL;
 	h->counter_map = (void *)h
 		+ sizeof(STRUCT_TC_HANDLE)
 		+ size;
-	strncpy(h->info.name, tablename, sizeof(h->info.name));
-	h->info.name[sizeof(h->info.name)-1] = '\0';
-	strncpy(h->entries.name, tablename, sizeof(h->entries.name));
-	h->entries.name[sizeof(h->entries.name)-1] = '\0';
+	strncpy(h->info.name, tablename, sizeof(h->info.name) - 1);
+	strncpy(h->entries.name, tablename, sizeof(h->entries.name) - 1);
 
 	return h;
 }
-- 
2.24.0

Re: [arptables PATCH 2/3] Eliminate compiler warning about size passed to strncmp()

[Pablo Neira Ayuso]

On Thu, Nov 21, 2019 at 12:15:58PM +0100, Phil Sutter wrote:
> Gcc complains about the size being equal to destination size, despite
> the nul character being explicitly set in following line.
> 
> Reduce size by one to make gcc happy. While being at it, drop the
> explicit nul character assignment - it is not needed as the buffer was
> allocated by calloc().
> 
> Fixes: 8f586939999e0 ("fix potential buffer overflows reported by static analysis")
> Signed-off-by: Phil Sutter <phil@nwl.cc>

Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>

Re: [arptables PATCH 1/3] Add .gitignore

[Pablo Neira Ayuso]

On Thu, Nov 21, 2019 at 12:15:57PM +0100, Phil Sutter wrote:
> Ignore temporary files, created arptables-legacy binary and any present
> tags file.
> 
> Signed-off-by: Phil Sutter <phil@nwl.cc>

Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>

Re: [arptables PATCH 3/3] libarptc: Simplify alloc_handle by using calloc()

[Pablo Neira Ayuso]

On Thu, Nov 21, 2019 at 12:15:59PM +0100, Phil Sutter wrote:
> No need to explicitly set fields to zero when using calloc().

Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>