From eae21beecb95a3b69ee5c38a659f774e171d730e Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Thu, 8 Jan 2026 12:35:04 +0100 Subject: [PATCH] EFI/CPER: don't go past the ARM processor CPER record buffer There's a logic inside GHES/CPER to detect if the section_length is too small, but it doesn't detect if it is too big. Currently, if the firmware receives an ARM processor CPER record stating that a section length is big, kernel will blindly trust section_length, producing a very long dump. For instance, a 67 bytes record with ERR_INFO_NUM set 46198 and section length set to 854918320 would dump a lot of data going a way past the firmware memory-mapped area. Fix it by adding a logic to prevent it to go past the buffer if ERR_INFO_NUM is too big, making it report instead: [Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 1 [Hardware Error]: event severity: recoverable [Hardware Error]: Error 0, type: recoverable [Hardware Error]: section_type: ARM processor error [Hardware Error]: MIDR: 0xff304b2f8476870a [Hardware Error]: section length: 854918320, CPER size: 67 [Hardware Error]: section length is too big [Hardware Error]: firmware-generated error record is incorrect [Hardware Error]: ERR_INFO_NUM is 46198 Signed-off-by: Mauro Carvalho Chehab Reviewed-by: Jonathan Cameron Acked-by: Ard Biesheuvel Reviewed-by: Hanjun Guo [ rjw: Subject and changelog tweaks ] Link: https://patch.msgid.link/41cd9f6b3ace3cdff7a5e864890849e4b1c58b63.1767871950.git.mchehab+huawei@kernel.org Signed-off-by: Rafael J. Wysocki --- drivers/firmware/efi/cper-arm.c | 12 ++++++++---- drivers/firmware/efi/cper.c | 3 ++- include/linux/cper.h | 3 ++- 3 files changed, 12 insertions(+), 6 deletions(-) diff --git a/drivers/firmware/efi/cper-arm.c b/drivers/firmware/efi/cper-arm.c index 76542a53e2027..b21cb1232d820 100644 --- a/drivers/firmware/efi/cper-arm.c +++ b/drivers/firmware/efi/cper-arm.c @@ -226,7 +226,8 @@ static void cper_print_arm_err_info(const char *pfx, u32 type, } void cper_print_proc_arm(const char *pfx, - const struct cper_sec_proc_arm *proc) + const struct cper_sec_proc_arm *proc, + u32 length) { int i, len, max_ctx_type; struct cper_arm_err_info *err_info; @@ -238,9 +239,12 @@ void cper_print_proc_arm(const char *pfx, len = proc->section_length - (sizeof(*proc) + proc->err_info_num * (sizeof(*err_info))); - if (len < 0) { - printk("%ssection length: %d\n", pfx, proc->section_length); - printk("%ssection length is too small\n", pfx); + + if (len < 0 || proc->section_length > length) { + printk("%ssection length: %d, CPER size: %d\n", + pfx, proc->section_length, length); + printk("%ssection length is too %s\n", pfx, + (len < 0) ? "small" : "big"); printk("%sfirmware-generated error record is incorrect\n", pfx); printk("%sERR_INFO_NUM is %d\n", pfx, proc->err_info_num); return; diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c index 0232bd040f61c..88fc0293f8762 100644 --- a/drivers/firmware/efi/cper.c +++ b/drivers/firmware/efi/cper.c @@ -659,7 +659,8 @@ cper_estatus_print_section(const char *pfx, struct acpi_hest_generic_data *gdata printk("%ssection_type: ARM processor error\n", newpfx); if (gdata->error_data_length >= sizeof(*arm_err)) - cper_print_proc_arm(newpfx, arm_err); + cper_print_proc_arm(newpfx, arm_err, + gdata->error_data_length); else goto err_section_too_small; #endif diff --git a/include/linux/cper.h b/include/linux/cper.h index 5b1236d8c65bb..440b35e459e53 100644 --- a/include/linux/cper.h +++ b/include/linux/cper.h @@ -595,7 +595,8 @@ void cper_mem_err_pack(const struct cper_sec_mem_err *, const char *cper_mem_err_unpack(struct trace_seq *, struct cper_mem_err_compact *); void cper_print_proc_arm(const char *pfx, - const struct cper_sec_proc_arm *proc); + const struct cper_sec_proc_arm *proc, + u32 length); void cper_print_proc_ia(const char *pfx, const struct cper_sec_proc_ia *proc); int cper_mem_err_location(struct cper_mem_err_compact *mem, char *msg); -- 2.47.3