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[PATCH] readelf: Add overflow checking to print_gdb_index_section dataend checks.
- From: Mark Wielaard <mjw at redhat dot com>
- To: elfutils-devel at lists dot fedorahosted dot org
- Date: Fri, 17 Apr 2015 20:05:53 +0200
- Subject: [PATCH] readelf: Add overflow checking to print_gdb_index_section dataend checks.
https://bugzilla.redhat.com/show_bug.cgi?id=1170810#c29
Signed-off-by: Mark Wielaard <mjw@redhat.com>
---
src/ChangeLog | 5 +++++
src/readelf.c | 24 +++++++++++++++---------
2 files changed, 20 insertions(+), 9 deletions(-)
diff --git a/src/ChangeLog b/src/ChangeLog
index c8ddff6..6985b58 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2015-03-17 Mark Wielaard <mjw@redhat.com>
+
+ * readelf.c (print_gdb_index_section): Add overflow checking for
+ dataend checks.
+
2015-03-14 Mark Wielaard <mjw@redhat.com>
* nm.c (INTERNAL_ERROR): Remove __DATE__.
diff --git a/src/readelf.c b/src/readelf.c
index 23bd73f..b717757 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -8011,6 +8011,12 @@ print_gdb_index_section (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr,
uint32_t const_off = read_4ubyte_unaligned (dbg, readp);
printf (gettext (" constant offset: %#" PRIx32 "\n"), const_off);
+ if (unlikely ((size_t) (dataend - (const unsigned char *) data->d_buf)
+ < const_off))
+ goto invalid_data;
+
+ const unsigned char *const_start = data->d_buf + const_off;
+
readp = data->d_buf + cu_off;
const unsigned char *nextp = data->d_buf + tu_off;
@@ -8021,7 +8027,7 @@ print_gdb_index_section (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr,
cu_off, cu_nr);
size_t n = 0;
- while (readp + 16 <= dataend && n < cu_nr)
+ while (dataend - readp >= 16 && n < cu_nr)
{
uint64_t off = read_8ubyte_unaligned (dbg, readp);
readp += 8;
@@ -8043,7 +8049,7 @@ print_gdb_index_section (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr,
tu_off, tu_nr);
n = 0;
- while (readp + 24 <= dataend && n < tu_nr)
+ while (dataend - readp >= 24 && n < tu_nr)
{
uint64_t off = read_8ubyte_unaligned (dbg, readp);
readp += 8;
@@ -8069,7 +8075,7 @@ print_gdb_index_section (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr,
addr_off, addr_nr);
n = 0;
- while (readp + 20 <= dataend && n < addr_nr)
+ while (dataend - readp >= 20 && n < addr_nr)
{
uint64_t low = read_8ubyte_unaligned (dbg, readp);
readp += 8;
@@ -8090,7 +8096,7 @@ print_gdb_index_section (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr,
}
readp = data->d_buf + sym_off;
- nextp = data->d_buf + const_off;
+ nextp = const_start;
size_t sym_nr = (nextp - readp) / 8;
printf (gettext ("\n Symbol table at offset %#" PRIx32
@@ -8098,7 +8104,7 @@ print_gdb_index_section (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr,
addr_off, sym_nr);
n = 0;
- while (readp + 8 <= dataend && n < sym_nr)
+ while (dataend - readp >= 8 && n < sym_nr)
{
uint32_t name = read_4ubyte_unaligned (dbg, readp);
readp += 4;
@@ -8108,15 +8114,15 @@ print_gdb_index_section (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr,
if (name != 0 || vector != 0)
{
- const unsigned char *sym = data->d_buf + const_off + name;
- if (unlikely (sym > dataend
+ const unsigned char *sym = const_start + name;
+ if (unlikely ((size_t) (dataend - const_start) < name
|| memchr (sym, '\0', dataend - sym) == NULL))
goto invalid_data;
printf (" [%4zu] symbol: %s, CUs: ", n, sym);
- const unsigned char *readcus = data->d_buf + const_off + vector;
- if (unlikely (readcus + 4 > dataend))
+ const unsigned char *readcus = const_start + vector;
+ if (unlikely ((size_t) (dataend - const_start) < vector))
goto invalid_data;
uint32_t cus = read_4ubyte_unaligned (dbg, readcus);
while (cus--)
--
1.8.3.1