From: Alan Modra <amodra@gmail.com>
To: binutils@sourceware.org
Subject: asan: readelf buffer overflow and abort
Date: Fri, 25 Sep 2020 11:54:12 +0930 [thread overview]
Message-ID: <20200925022411.GN5452@bubble.grove.modra.org> (raw)
* elfcomm.c (byte_put_little_endian, byte_put_big_endian): Support
more field sizes.
* readelf.c (target_specific_reloc_handling <MSP430>): Limit
allowed reloc_size. Don't read_leb128 outside of section.
diff --git a/binutils/elfcomm.c b/binutils/elfcomm.c
index 37f9dbe7ee..81742bf75b 100644
--- a/binutils/elfcomm.c
+++ b/binutils/elfcomm.c
@@ -67,66 +67,31 @@ void (*byte_put) (unsigned char *, elf_vma, int);
void
byte_put_little_endian (unsigned char * field, elf_vma value, int size)
{
- switch (size)
+ if (size <= 0 || size > 8)
{
- case 8:
- field[7] = (((value >> 24) >> 24) >> 8) & 0xff;
- field[6] = ((value >> 24) >> 24) & 0xff;
- field[5] = ((value >> 24) >> 16) & 0xff;
- field[4] = ((value >> 24) >> 8) & 0xff;
- /* Fall through. */
- case 4:
- field[3] = (value >> 24) & 0xff;
- /* Fall through. */
- case 3:
- field[2] = (value >> 16) & 0xff;
- /* Fall through. */
- case 2:
- field[1] = (value >> 8) & 0xff;
- /* Fall through. */
- case 1:
- field[0] = value & 0xff;
- break;
-
- default:
error (_("Unhandled data length: %d\n"), size);
abort ();
}
+ while (size--)
+ {
+ *field++ = value & 0xff;
+ value >>= 8;
+ }
}
void
byte_put_big_endian (unsigned char * field, elf_vma value, int size)
{
- switch (size)
+ if (size <= 0 || size > 8)
{
- case 8:
- field[7] = value & 0xff;
- field[6] = (value >> 8) & 0xff;
- field[5] = (value >> 16) & 0xff;
- field[4] = (value >> 24) & 0xff;
- value >>= 16;
- value >>= 16;
- /* Fall through. */
- case 4:
- field[3] = value & 0xff;
- value >>= 8;
- /* Fall through. */
- case 3:
- field[2] = value & 0xff;
- value >>= 8;
- /* Fall through. */
- case 2:
- field[1] = value & 0xff;
- value >>= 8;
- /* Fall through. */
- case 1:
- field[0] = value & 0xff;
- break;
-
- default:
error (_("Unhandled data length: %d\n"), size);
abort ();
}
+ while (size--)
+ {
+ field[size] = value & 0xff;
+ value >>= 8;
+ }
}
elf_vma (*byte_get) (const unsigned char *, int);
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 95720ea055..9ba4e29a65 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -12622,7 +12622,7 @@ target_specific_reloc_handling (Filedata * filedata,
if (saved_sym != NULL)
{
bfd_vma value;
- unsigned int reloc_size;
+ unsigned int reloc_size = 0;
int leb_ret = 0;
switch (reloc_type)
{
@@ -12631,15 +12631,16 @@ target_specific_reloc_handling (Filedata * filedata,
break;
case 11: /* R_MSP430_GNU_SET_ULEB128 */
case 22: /* R_MSP430X_GNU_SET_ULEB128 */
- read_leb128 (start + reloc->r_offset, end, FALSE,
- &reloc_size, &leb_ret);
+ if (reloc->r_offset < (size_t) (end - start))
+ read_leb128 (start + reloc->r_offset, end, FALSE,
+ &reloc_size, &leb_ret);
break;
default:
reloc_size = 2;
break;
}
- if (leb_ret != 0)
+ if (leb_ret != 0 || reloc_size == 0 || reloc_size > 8)
error (_("MSP430 ULEB128 field at 0x%lx contains invalid "
"ULEB128 value\n"),
(long) reloc->r_offset);
--
Alan Modra
Australia Development Lab, IBM
reply other threads:[~2020-09-25 2:24 UTC|newest]
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