[edk2-devel] [PATCH v4 03/12] BaseTools/VfrCompile: Fix potential buffer overwrites

[Michael Kubacki]

From: Michael Kubacki <michael.kubacki at microsoft.com>

While more portable methods exist to handle these cases, this change
does not attempt to do more than fix the immediate problem and
follow the conventions already established in this code.

`snprintf()` is introduced as the minimum improvement apart from
making the buffers larger.

Fixes the following CodeQL alerts:

1. Failure on line 2339 in
   BaseTools/Source/C/VfrCompile/Pccts/antlr/gen.c

   - Type: Potentially overrunning write
   - Severity: Critical
   - Problem: This 'call to sprintf' operation requires 17 bytes but
     the destination is only 16 bytes.

2. Failure on line 2341 in
   BaseTools/Source/C/VfrCompile/Pccts/antlr/gen.c

   - Type: Potentially overrunning write
   - Severity: Critical
   - Problem: This 'call to sprintf' operation requires 17 bytes but
     the destination is only 16 bytes.

3. Failure on line 1309 in
   BaseTools/Source/C/VfrCompile/Pccts/antlr/main.c

   - Type: Potentially overrunning write
   - Severity: Critical
   - Problem: This 'call to sprintf' operation requires 25 bytes but
     the destination is only 20 bytes.

Cc: Bob Feng <bob.c.feng at intel.com>
Cc: Liming Gao <gaoliming at byosoft.com.cn>
Cc: Michael D Kinney <michael.d.kinney at intel.com>
Cc: Sean Brogan <sean.brogan at microsoft.com>
Cc: Yuwei Chen <yuwei.chen at intel.com>
Signed-off-by: Michael Kubacki <michael.kubacki at microsoft.com>
Reviewed-by: Liming Gao <gaoliming at byosoft.com.cn>
Reviewed-by: Michael D Kinney <michael.d.kinney at intel.com>
---
 BaseTools/Source/C/VfrCompile/Pccts/antlr/gen.c  | 10 +++++-----
 BaseTools/Source/C/VfrCompile/Pccts/antlr/main.c |  4 ++--
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/BaseTools/Source/C/VfrCompile/Pccts/antlr/gen.c b/BaseTools/Source/C/VfrCompile/Pccts/antlr/gen.c
index 8e41239f4751..33d9cac4c7de 100644
--- a/BaseTools/Source/C/VfrCompile/Pccts/antlr/gen.c
+++ b/BaseTools/Source/C/VfrCompile/Pccts/antlr/gen.c
@@ -2331,14 +2331,14 @@ TokNode *p;
 			set_nameErrSet = bufErrSet;								/* MR23 */
 		}
 		else {					/* wild card */
-			static char buf[sizeof("zzerr")+10];
-			static char bufErrSet[sizeof("zzerr")+10];
+			static char buf[sizeof("zzerr")+11];
+			static char bufErrSet[sizeof("zzerr")+11];
 			int n = DefErrSet( &b, 0, NULL );
 			int nErrSet = DefErrSetWithSuffix(0, &bErrSet, 1, NULL, "_set");
-			if ( GenCC ) sprintf(buf, "err%d", n);
-			else sprintf(buf, "zzerr%d", n);
+			if ( GenCC ) snprintf(buf, 11, "err%d", n);
+			else snprintf(buf, 11, "zzerr%d", n);
 			if ( GenCC ) sprintf(bufErrSet, "err%d", nErrSet);
-			else sprintf(bufErrSet, "zzerr%d", nErrSet);
+			else snprintf(bufErrSet, 11, "zzerr%d", nErrSet);
 			set_name = buf;
 			set_nameErrSet = bufErrSet;
 		}
diff --git a/BaseTools/Source/C/VfrCompile/Pccts/antlr/main.c b/BaseTools/Source/C/VfrCompile/Pccts/antlr/main.c
index 051ee4ec5d28..488b4b90461c 100644
--- a/BaseTools/Source/C/VfrCompile/Pccts/antlr/main.c
+++ b/BaseTools/Source/C/VfrCompile/Pccts/antlr/main.c
@@ -1295,7 +1295,7 @@ int token;
 #endif
 {
 	int     j;
-        static    char    imag_name[20];
+        static    char    imag_name[25];
 
 	/* look in all lexclasses for the token */
 	if ( TokenString(token) != NULL ) return TokenString(token);
@@ -1306,7 +1306,7 @@ int token;
 	}
 
     if (1) {
-      sprintf(imag_name,"UnknownToken#%d",token);           /* MR13 */
+      snprintf(imag_name, 25, "UnknownToken#%d", token);    /* MR13 */
       return imag_name;                                     /* MR13 */
     }
 
-- 
2.39.2.windows.1



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