[glibc/arm/morello/main] Fix OOB read in stdlib thousand separator handling

[glibc/arm/morello/main] Fix OOB read in stdlib thousand separator handling

[Szabolcs Nagy]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=85c6eba32a3c1f227ff89bbd23d6c97cdf76892b

commit 85c6eba32a3c1f227ff89bbd23d6c97cdf76892b
Author: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date:   Tue Oct 11 15:24:41 2022 +0100

    Fix OOB read in stdlib thousand separator handling
    
    __correctly_grouped_prefixmb only worked with thousands_len == 1,
    otherwise it read past the end of cp or thousands.
    
    Avoid OOB access by considering thousands_len when initializing cp.
    
    On morello with strict bounds checking this fixes
    
    FAIL: stdlib/tst-strtod4
    FAIL: stdlib/tst-strtod5i
    
    both of which set cs_CZ.UTF-8 locale that has 3 byte thousands_len.

Diff:
---
 stdlib/grouping.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/stdlib/grouping.c b/stdlib/grouping.c
index be7922f5fd..4622897488 100644
--- a/stdlib/grouping.c
+++ b/stdlib/grouping.c
@@ -64,9 +64,17 @@ __correctly_grouped_prefixmb (const STRING_TYPE *begin, const STRING_TYPE *end,
   thousands_len = strlen (thousands);
 #endif
 
+#ifdef USE_WIDE_CHAR
   while (end > begin)
+#else
+  while (end - begin >= thousands_len)
+#endif
     {
+#ifdef USE_WIDE_CHAR
       const STRING_TYPE *cp = end - 1;
+#else
+      const STRING_TYPE *cp = end - thousands_len;
+#endif
       const char *gp = grouping;
 
       /* Check first group.  */

[glibc/arm/morello/main] Fix OOB read in stdlib thousand separator handling

[Szabolcs Nagy]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=a3bae65b44690a5ca63fbe7ce77fa4269467bde4

commit a3bae65b44690a5ca63fbe7ce77fa4269467bde4
Author: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date:   Tue Oct 11 15:24:41 2022 +0100

    Fix OOB read in stdlib thousand separator handling
    
    __correctly_grouped_prefixmb only worked with thousands_len == 1,
    otherwise it read past the end of cp or thousands.
    
    Avoid OOB access by considering thousands_len when initializing cp.
    
    On morello with strict bounds checking this fixes
    
    FAIL: stdlib/tst-strtod4
    FAIL: stdlib/tst-strtod5i
    
    both of which set cs_CZ.UTF-8 locale that has 3 byte thousands_len.

Diff:
---
 stdlib/grouping.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/stdlib/grouping.c b/stdlib/grouping.c
index be7922f5fd..4622897488 100644
--- a/stdlib/grouping.c
+++ b/stdlib/grouping.c
@@ -64,9 +64,17 @@ __correctly_grouped_prefixmb (const STRING_TYPE *begin, const STRING_TYPE *end,
   thousands_len = strlen (thousands);
 #endif
 
+#ifdef USE_WIDE_CHAR
   while (end > begin)
+#else
+  while (end - begin >= thousands_len)
+#endif
     {
+#ifdef USE_WIDE_CHAR
       const STRING_TYPE *cp = end - 1;
+#else
+      const STRING_TYPE *cp = end - thousands_len;
+#endif
       const char *gp = grouping;
 
       /* Check first group.  */