From: Ruipeng Qi <[email protected]> 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: Ruipeng Qi <[email protected]> --- fs/pstore/ram_core.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index f1848cdd6d34..f8b9b47e8b24 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -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 -- 2.25.1
