In the Linux kernel, the following vulnerability has been resolved:

ASoC: meson: Keep link pointers valid on realloc failure

meson_card_reallocate_links() grows the DAI link and private data arrays with two consecutive krealloc() calls and updates the owner pointers only after both calls have succeeded.

A successful krealloc() may move the data: it frees the old block and returns a new one. When that happens for the link array and the second krealloc() then fails, card->dai_link still points to the block that krealloc() already freed, and the error path frees the new block too. The probe error path then calls meson_card_clean_references(), which dereferences card->dai_link and kfree()s it again, resulting in a use-after-free and a double free.

Commit card->dai_link and card->num_links right after the first krealloc() succeeds, so the pointer always refers to a valid allocation that meson_card_clean_references() can walk and free. krealloc() with __GFP_ZERO zero-initializes the added entries, so walking them on the error path is safe. With both failure paths reduced to a plain return, drop the goto labels and the error message.

In the Linux kernel, the following vulnerability has been resolved:

ASoC: meson: Keep link pointers valid on realloc failure

meson_card_reallocate_links() grows the DAI link and private data arrays with two consecutive krealloc() calls and updates the owner pointers only after both calls have succeeded.

A successful krealloc() may move the data: it frees the old block and returns a new one. When that happens for the link array and the second krealloc() then fails, card->dai_link still points to the block that krealloc() already freed, and the error path frees the new block too. The probe error path then calls meson_card_clean_references(), which dereferences card->dai_link and kfree()s it again, resulting in a use-after-free and a double free.

Commit card->dai_link and card->num_links right after the first krealloc() succeeds, so the pointer always refers to a valid allocation that meson_card_clean_references() can walk and free. krealloc() with __GFP_ZERO zero-initializes the added entries, so walking them on the error path is safe. With both failure paths reduced to a plain return, drop the goto labels and the error message.

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:Pro:18.04:LTS: linux-aws-5.4, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:Pro:18.04:LTS: linux-azure-5.4, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3 and 219 more

In the Linux kernel, the following vulnerability has been resolved: ASoC: meson: Keep link pointers valid on realloc failure meson_card_reallocate_links() grows the DAI link and private data arrays with two consecutive krealloc() calls and updates the owner pointers only after both calls have succeeded. A successful krealloc() may move the data: it frees the old block and returns a new one. When that happens for the link array and the second krealloc() then fails, card->dai_link still points to the block that krealloc() already freed, and the error path frees the new block too. The probe error path then calls meson_card_clean_references(), which dereferences card->dai_link and kfree()s it again, resulting in a use-after-free and a double free. Commit card->dai_link and card->num_links right after the first krealloc() succeeds, so the pointer always refers to a valid allocation that meson_card_clean_references() can walk and free. krealloc() with __GFP_ZERO zero-initializes the added entries, so walking them on the error path is safe. With both failure paths reduced to a plain return, drop the goto labels and the error message.