Re: [PATCH] libdwfl: Make sure elf_getdata_rawchunk size_t doesn't overflow find_dynsym.

Re: [PATCH] libdwfl: Make sure elf_getdata_rawchunk size_t doesn't overflow find_dynsym.

[Mark Wielaard]

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On Sat, 2014-12-13 at 22:29 +0100, Mark Wielaard wrote:
> +2014-12-13  Mark Wielaard  <mjw@redhat.com>
> +
> +	* dwfl_module_getdwarf.c (find_dynsym): elf_getdata_rawchunk takes
> +	a size_t, make sure it doesn't overflow.

I pushed this to master.

[PATCH] libdwfl: Make sure elf_getdata_rawchunk size_t doesn't overflow find_dynsym.

[Mark Wielaard]

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Signed-off-by: Mark Wielaard <mjw@redhat.com>
---
 libdwfl/ChangeLog              |  5 +++++
 libdwfl/dwfl_module_getdwarf.c | 10 +++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index 66e642f..99d555f 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,3 +1,8 @@
+2014-12-13  Mark Wielaard  <mjw@redhat.com>
+
+	* dwfl_module_getdwarf.c (find_dynsym): elf_getdata_rawchunk takes
+	a size_t, make sure it doesn't overflow.
+
 2014-12-09  Mark Wielaard  <mjw@redhat.com>
 
 	* dwfl_segment_report_module.c (handle_file_note): Check count doesn't
diff --git a/libdwfl/dwfl_module_getdwarf.c b/libdwfl/dwfl_module_getdwarf.c
index c2e9e59..ab9bd48 100644
--- a/libdwfl/dwfl_module_getdwarf.c
+++ b/libdwfl/dwfl_module_getdwarf.c
@@ -768,7 +768,15 @@ find_dynsym (Dwfl_Module *mod)
 					      * sizeof (Elf32_Word)
 					      * header->maskwords));
 
-		    data = elf_getdata_rawchunk (mod->main.elf, buckets_at,
+		    // elf_getdata_rawchunk takes a size_t, make sure it
+		    // doesn't overflow.
+#if SIZE_MAX <= UINT32_MAX
+		    if (nbuckets > SIZE_MAX / sizeof (Elf32_Word))
+		      data = NULL;
+		    else
+#endif
+		      data
+			 = elf_getdata_rawchunk (mod->main.elf, buckets_at,
 						 nbuckets * sizeof (Elf32_Word),
 						 ELF_T_WORD);
 		    if (data != NULL && symndx < nbuckets)
-- 
2.1.0