RISC-V: Fix out-of-bounds accesses in init_resources()

init_resources() allocates an array of resources, based on the current
total number of memory regions and reserved memory regions.  However,
allocating this array using memblock_alloc() might increase the number
of reserved memory regions.  If that happens, populating the array later
based on the new number of regions will cause out-of-bounds writes
beyond the end of the allocated array.

Fix this by allocating one more entry, which may or may not be used.

Fixes: 797f0375dd2ef5cd ("RISC-V: Do not allocate memblock while iterating reserved memblocks")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index e85bacff1b5075ee3b704f7a65e40d102d0a9de3..f8f15332caa20263e995a31d1d588e923786eb1d 100644 (file)
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -147,7 +147,8 @@ static void __init init_resources(void)
        bss_res.end = __pa_symbol(__bss_stop) - 1;
        bss_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
 
-       mem_res_sz = (memblock.memory.cnt + memblock.reserved.cnt) * sizeof(*mem_res);
+       /* + 1 as memblock_alloc() might increase memblock.reserved.cnt */
+       mem_res_sz = (memblock.memory.cnt + memblock.reserved.cnt + 1) * sizeof(*mem_res);
        mem_res = memblock_alloc(mem_res_sz, SMP_CACHE_BYTES);
        if (!mem_res)
                panic("%s: Failed to allocate %zu bytes\n", __func__, mem_res_sz);