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net: macb: Add __nonstring annotations for unterminated strings

PATCH Superseded Kees Cook 3 participants 4 messages Mar 11, 2025 – Mar 18, 2025

Subsystems (3)
Networking Network drivers Atmel MACB Ethernet driver

v2 of 3 Superseded Latest is v3 →

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Kees Cook

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#0 lore raw

PATCH v2 1/1 net: macb: Add __nonstring annotations for unterminated strings

When a character array without a terminating NUL character has a static initializer, GCC 15's -Wunterminated-string-initialization will only warn if the array lacks the "nonstring" attribute[1]. Mark the arrays with __nonstring to and correctly identify the char array as "not a C string" and thereby eliminate the warning.

Link https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1]
Signed-off-by Kees Cook <[email protected]>

---
v1: https://lore.kernel.org/lkml/[email protected]/
v2: switch to __nonstring annotation
Cc: Nicolas Ferre <[email protected]>
Cc: Claudiu Beznea <[email protected]>
Cc: Andrew Lunn <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: [email protected]

---
 drivers/net/ethernet/cadence/macb.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
drivers/net/ethernet/cadence/macb.h +2 -1
index 2847278d9cd4..003483073223 100644
@@ -1027,7 +1027,7 @@ struct gem_stats {
  * this register should contribute to.
  */
 struct gem_statistic {
-	char stat_string[ETH_GSTRING_LEN];
+	char stat_string[ETH_GSTRING_LEN] __nonstring;
 	int offset;
 	u32 stat_bits;
 };

@@ -1068,6 +1068,7 @@ static const struct gem_statistic gem_statistics[] = {
 	GEM_STAT_TITLE(TX512CNT, "tx_512_1023_byte_frames"),
 	GEM_STAT_TITLE(TX1024CNT, "tx_1024_1518_byte_frames"),
 	GEM_STAT_TITLE(TX1519CNT, "tx_greater_than_1518_byte_frames"),
+
 	GEM_STAT_TITLE_BITS(TXURUNCNT, "tx_underrun",
 			    GEM_BIT(NDS_TXERR)|GEM_BIT(NDS_TXFIFOERR)),
 	GEM_STAT_TITLE_BITS(SNGLCOLLCNT, "tx_single_collision_frames",
Signature · 1 line
2.34.1
Reviewed-by on v2 1/1
#1 lore raw
Quoted 5 lines · Kees Cook

When a character array without a terminating NUL character has a static initializer, GCC 15's -Wunterminated-string-initialization will only warn if the array lacks the "nonstring" attribute[1]. Mark the arrays with __nonstring to and correctly identify the char array as "not a C

s/__nonstring to and correctly/__nonstring to correctly/ ?

Quoted 33 lines

string" and thereby eliminate the warning.

Link https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1]
Signed-off-by Kees Cook <[email protected]>

---
v1: https://lore.kernel.org/lkml/[email protected]/
v2: switch to __nonstring annotation
Cc: Nicolas Ferre <[email protected]>
Cc: Claudiu Beznea <[email protected]>
Cc: Andrew Lunn <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: [email protected]

---
 drivers/net/ethernet/cadence/macb.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
drivers/net/ethernet/cadence/macb.h +1 -1
index 2847278d9cd4..003483073223 100644
@@ -1027,7 +1027,7 @@ struct gem_stats {
  * this register should contribute to.
  */
 struct gem_statistic {
-       char stat_string[ETH_GSTRING_LEN];
+       char stat_string[ETH_GSTRING_LEN] __nonstring;
        int offset;
        u32 stat_bits;
 };

drivers/net/ethernet/cadence/macb.h static const struct gem_statistic gem_statistics[] = { · line 1071

Quoted 4 lines
drivers/net/ethernet/cadence/macb.h +1 -0
@@ -1068,6 +1068,7 @@ static const struct gem_statistic gem_statistics[] = {
        GEM_STAT_TITLE(TX512CNT, "tx_512_1023_byte_frames"),
        GEM_STAT_TITLE(TX1024CNT, "tx_1024_1518_byte_frames"),
        GEM_STAT_TITLE(TX1519CNT, "tx_greater_than_1518_byte_frames"),
+

Is this an errant inclusion? :-)

Reviewed-by Bill Wendling <[email protected]>
Quoted 7 lines
drivers/net/ethernet/cadence/macb.h +0 -1
        GEM_STAT_TITLE_BITS(TXURUNCNT, "tx_underrun",
                            GEM_BIT(NDS_TXERR)|GEM_BIT(NDS_TXFIFOERR)),
        GEM_STAT_TITLE_BITS(SNGLCOLLCNT, "tx_single_collision_frames",
--

2.34.1

author
#2 lore raw
Quoted 8 lines · Bill Wendling
Quoted 5 lines · Kees Cook

When a character array without a terminating NUL character has a static initializer, GCC 15's -Wunterminated-string-initialization will only warn if the array lacks the "nonstring" attribute[1]. Mark the arrays with __nonstring to and correctly identify the char array as "not a C

s/__nonstring to and correctly/__nonstring to correctly/ ?

Whoops. Rewriting glitch. Yes, "and" should be dropped. I will fix this locally for all the patches with the same language and send v3 for this one.

Quoted 32 lines
Quoted 32 lines

string" and thereby eliminate the warning.

Link https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1]
Signed-off-by Kees Cook <[email protected]>

---
v1: https://lore.kernel.org/lkml/[email protected]/
v2: switch to __nonstring annotation
Cc: Nicolas Ferre <[email protected]>
Cc: Claudiu Beznea <[email protected]>
Cc: Andrew Lunn <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: [email protected]

---
 drivers/net/ethernet/cadence/macb.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
drivers/net/ethernet/cadence/macb.h +1 -1
index 2847278d9cd4..003483073223 100644
@@ -1027,7 +1027,7 @@ struct gem_stats {
  * this register should contribute to.
  */
 struct gem_statistic {
-       char stat_string[ETH_GSTRING_LEN];
+       char stat_string[ETH_GSTRING_LEN] __nonstring;
        int offset;
        u32 stat_bits;
Quoted 8 lines

drivers/net/ethernet/cadence/macb.h static const struct gem_statistic gem_statistics[] = { · line 1071

Quoted 6 lines
drivers/net/ethernet/cadence/macb.h +1 -0
 };

@@ -1068,6 +1068,7 @@ static const struct gem_statistic gem_statistics[] = {
        GEM_STAT_TITLE(TX512CNT, "tx_512_1023_byte_frames"),
        GEM_STAT_TITLE(TX1024CNT, "tx_1024_1518_byte_frames"),
        GEM_STAT_TITLE(TX1519CNT, "tx_greater_than_1518_byte_frames"),
+

Is this an errant inclusion? :-)

Ah, yeah, I had removed the truncation change but the whitespace change stuck around. Also fixing!

Quoted 2 lines
Reviewed-by Bill Wendling <[email protected]>

Thanks!

-Kees

Signature · 1 line
Kees Cook
reviewer
#3 lore raw
In reply to Kees Cook
Quoted 28 lines · Kees Cook

When a character array without a terminating NUL character has a static initializer, GCC 15's -Wunterminated-string-initialization will only warn if the array lacks the "nonstring" attribute[1]. Mark the arrays with __nonstring to and correctly identify the char array as "not a C string" and thereby eliminate the warning.

Link https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1]
Signed-off-by Kees Cook <[email protected]>

---
v1: https://lore.kernel.org/lkml/[email protected]/
v2: switch to __nonstring annotation
Cc: Nicolas Ferre <[email protected]>
Cc: Claudiu Beznea <[email protected]>
Cc: Andrew Lunn <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: [email protected]

---
 drivers/net/ethernet/cadence/macb.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
drivers/net/ethernet/cadence/macb.h +0 -0
index 2847278d9cd4..003483073223 100644

drivers/net/ethernet/cadence/macb.h struct gem_stats { · line 1030

Quoted 5 lines
drivers/net/ethernet/cadence/macb.h +1 -1
@@ -1027,7 +1027,7 @@ struct gem_stats {
  * this register should contribute to.
  */
 struct gem_statistic {
-	char stat_string[ETH_GSTRING_LEN];
+	char stat_string[ETH_GSTRING_LEN] __nonstring;

Hi Kees, all,

I see where this is going, and I have no objections to it. But a member called *_string which is annotated as __nonstring does seem a somewhat unintuitive.

Quoted 15 lines
drivers/net/ethernet/cadence/macb.h +1 -0
 	int offset;
 	u32 stat_bits;
 };

@@ -1068,6 +1068,7 @@ static const struct gem_statistic gem_statistics[] = {
 	GEM_STAT_TITLE(TX512CNT, "tx_512_1023_byte_frames"),
 	GEM_STAT_TITLE(TX1024CNT, "tx_1024_1518_byte_frames"),
 	GEM_STAT_TITLE(TX1519CNT, "tx_greater_than_1518_byte_frames"),
+
 	GEM_STAT_TITLE_BITS(TXURUNCNT, "tx_underrun",
 			    GEM_BIT(NDS_TXERR)|GEM_BIT(NDS_TXFIFOERR)),
 	GEM_STAT_TITLE_BITS(SNGLCOLLCNT, "tx_single_collision_frames",
Signature · 1 line
2.34.1