Fix T45884: Crash copying keyframes

BLI_str_quoted_substrN could crash if the prefix wasn't found

1 files changed, 4 insertions, 3 deletions

diff --git a/source/blender/blenlib/intern/string.c b/source/blender/blenlib/intern/string.c
index 6d75f7c4131..6cc00fc60ee 100644
--- a/source/blender/blenlib/intern/string.c
+++ b/source/blender/blenlib/intern/string.c
@@ -379,12 +379,13 @@ escape_finish:
  */
 char *BLI_str_quoted_substrN(const char *__restrict str, const char *__restrict prefix)
 {
-	size_t prefixLen = strlen(prefix);
 	const char *startMatch, *endMatch;
-	
+
 	/* get the starting point (i.e. where prefix starts, and add prefixLen+1 to it to get be after the first " */
-	startMatch = strstr(str, prefix) + prefixLen + 1;
+	startMatch = strstr(str, prefix);
 	if (startMatch) {
+		const size_t prefixLen = strlen(prefix);
+		startMatch += prefixLen + 1;
 		/* get the end point (i.e. where the next occurance of " is after the starting point) */
 
 		endMatch = startMatch;