Commit 05363abc authored by Ruipeng Qi's avatar Ruipeng Qi Committed by Kees Cook
Browse files

pstore: ram_core: fix incorrect success return when vmap() fails 



In persistent_ram_vmap(), vmap() may return NULL on failure.

If offset is non-zero, adding offset_in_page(start) causes the function
to return a non-NULL pointer even though the mapping failed.
persistent_ram_buffer_map() therefore incorrectly returns success.

Subsequent access to prz->buffer may dereference an invalid address
and cause crashes.

Add proper NULL checking for vmap() failures.

Signed-off-by: default avatarRuipeng Qi <ruipengqi3@gmail.com>
Link: https://patch.msgid.link/20260203020358.3315299-1-ruipengqi3@gmail.com


Signed-off-by: default avatarKees Cook <kees@kernel.org>
parent 9448598b

fs/pstore/ram_core.c

+7 −0
Original line number Diff line number Diff line
@@ -446,6 +446,13 @@ static void *persistent_ram_vmap(phys_addr_t start, size_t size, 
	vaddr = vmap(pages, page_count, VM_MAP | VM_IOREMAP, prot);

	kfree(pages);



	/*

	 * vmap() may fail and return NULL. Do not add the offset in this

	 * case, otherwise a NULL mapping would appear successful.

	 */

	if (!vaddr)

		return NULL;



	/*

	 * Since vmap() uses page granularity, we must add the offset

	 * into the page here, to get the byte granularity address