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- 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
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