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Tue, 26 May 2026 20:29:59 -0700 (PDT) From: Wandun Chen To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, kexec@lists.infradead.org, iommu@lists.linux.dev, zhaomeijing@lixiang.com Cc: catalin.marinas@arm.com, will@kernel.org, chenhuacai@kernel.org, kernel@xen0n.name, pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr, robh@kernel.org, saravanak@kernel.org, akpm@linux-foundation.org, bhe@redhat.com, rppt@kernel.org, pasha.tatashin@soleen.com, pratyush@kernel.org, ruirui.yang@linux.dev, m.szyprowski@samsung.com, robin.murphy@arm.com, quic_obabatun@quicinc.com Subject: [PATCH v3 03/11] of: reserved_mem: avoid post-init UAF when alloc_reserved_mem_array() fails Date: Wed, 27 May 2026 11:29:09 +0800 Message-ID: <20260527032917.3385849-4-chenwandun1@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260527032917.3385849-1-chenwandun1@gmail.com> References: <20260527032917.3385849-1-chenwandun1@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Wandun Chen The global pointer 'reserved_mem' continues to reference the reserved_mem_array which lives in __initdata if alloc_reserved_mem_array() fails. of_reserved_mem_lookup() is exported for post-init use, that would dereference freed memory and trigger a use-after-free. So reset reserved_mem_count to 0 when alloc_reserved_mem_array() fails. Fixes: 00c9a452a235 ("of: reserved_mem: Add code to dynamically allocate reserved_mem array") Signed-off-by: Wandun Chen --- drivers/of/of_reserved_mem.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c index 313cbc57aa45..6d479381ff1f 100644 --- a/drivers/of/of_reserved_mem.c +++ b/drivers/of/of_reserved_mem.c @@ -69,29 +69,31 @@ static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size, * the initial static array is copied over to this new array and * the new array is used from this point on. */ -static void __init alloc_reserved_mem_array(void) +static bool __init alloc_reserved_mem_array(void) { struct reserved_mem *new_array; size_t alloc_size, copy_size, memset_size; + if (!total_reserved_mem_cnt) + return true; + alloc_size = array_size(total_reserved_mem_cnt, sizeof(*new_array)); if (alloc_size == SIZE_MAX) { pr_err("Failed to allocate memory for reserved_mem array with err: %d", -EOVERFLOW); - return; + goto fail; } new_array = memblock_alloc(alloc_size, SMP_CACHE_BYTES); if (!new_array) { pr_err("Failed to allocate memory for reserved_mem array with err: %d", -ENOMEM); - return; + goto fail; } copy_size = array_size(reserved_mem_count, sizeof(*new_array)); if (copy_size == SIZE_MAX) { memblock_free(new_array, alloc_size); - total_reserved_mem_cnt = MAX_RESERVED_REGIONS; pr_err("Failed to allocate memory for reserved_mem array with err: %d", -EOVERFLOW); - return; + goto fail; } memset_size = alloc_size - copy_size; @@ -100,6 +102,11 @@ static void __init alloc_reserved_mem_array(void) memset(new_array + reserved_mem_count, 0, memset_size); reserved_mem = new_array; + return true; + +fail: + reserved_mem_count = 0; + return false; } static void fdt_init_reserved_mem_node(unsigned long node, const char *uname, @@ -266,7 +273,8 @@ void __init fdt_scan_reserved_mem_late(void) } /* Attempt dynamic allocation of a new reserved_mem array */ - alloc_reserved_mem_array(); + if (!alloc_reserved_mem_array()) + return; if (__reserved_mem_check_root(node)) { pr_err("Reserved memory: unsupported node format, ignoring\n"); -- 2.43.0