| From 18490336d91da2b532277cba56473bfed1376fc4 Mon Sep 17 00:00:00 2001 |
| From: Daniel Axtens <dja@axtens.net> |
| Date: Thu, 21 Jan 2021 00:05:58 +1100 |
| Subject: [PATCH] io/gzio: Add init_dynamic_block() clean up if unpacking codes |
| fails |
| |
| init_dynamic_block() didn't clean up gzio->tl and td in some error |
| paths. This left td pointing to part of tl. Then in grub_gzio_close(), |
| when tl was freed the storage for td would also be freed. The code then |
| attempts to free td explicitly, performing a UAF and then a double free. |
| |
| Explicitly clean up tl and td in the error paths. |
| |
| Signed-off-by: Daniel Axtens <dja@axtens.net> |
| Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> |
| Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com> |
| --- |
| grub-core/io/gzio.c | 12 +++++++++--- |
| 1 file changed, 9 insertions(+), 3 deletions(-) |
| |
| diff --git a/grub-core/io/gzio.c b/grub-core/io/gzio.c |
| index 4a8eaea..4236f0f 100644 |
| --- a/grub-core/io/gzio.c |
| +++ b/grub-core/io/gzio.c |
| @@ -953,7 +953,7 @@ init_dynamic_block (grub_gzio_t gzio) |
| if ((unsigned) i + j > n) |
| { |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, "too many codes found"); |
| - return; |
| + goto fail; |
| } |
| while (j--) |
| ll[i++] = l; |
| @@ -966,7 +966,7 @@ init_dynamic_block (grub_gzio_t gzio) |
| if ((unsigned) i + j > n) |
| { |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, "too many codes found"); |
| - return; |
| + goto fail; |
| } |
| while (j--) |
| ll[i++] = 0; |
| @@ -981,7 +981,7 @@ init_dynamic_block (grub_gzio_t gzio) |
| if ((unsigned) i + j > n) |
| { |
| grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, "too many codes found"); |
| - return; |
| + goto fail; |
| } |
| while (j--) |
| ll[i++] = 0; |
| @@ -1019,6 +1019,12 @@ init_dynamic_block (grub_gzio_t gzio) |
| /* indicate we're now working on a block */ |
| gzio->code_state = 0; |
| gzio->block_len++; |
| + return; |
| + |
| + fail: |
| + huft_free (gzio->tl); |
| + gzio->td = NULL; |
| + gzio->tl = NULL; |
| } |
| |
| |
| -- |
| 2.14.2 |
| |