From: Mostafa Saleh <smostafa@google•com>
To: op-tee@lists•trustedfirmware.org, linux-kernel@vger•kernel.org,
kvmarm@lists•linux.dev, linux-arm-kernel@lists•infradead.org
Cc: maz@kernel•org, oupton@kernel•org, joey.gouly@arm•com,
suzuki.poulose@arm•com, catalin.marinas@arm•com,
jens.wiklander@linaro•org, sumit.garg@kernel•org,
sebastianene@google•com, vdonnefort@google•com,
sudeep.holla@kernel•org, Mostafa Saleh <smostafa@google•com>
Subject: [PATCH v4 2/5] firmware: arm_ffa: Fix out-of-bound writes in ffa_setup_and_transmit()
Date: Wed, 20 May 2026 20:49:45 +0000 [thread overview]
Message-ID: <20260520204948.2440882-3-smostafa@google.com> (raw)
In-Reply-To: <20260520204948.2440882-1-smostafa@google.com>
Sashiko (locally) reports multiple out-of-bound issues in
ffa_setup_and_transmit:
1) Writing ep_mem_access->reserved can write out of bounds for FFA
versions < 1.2 as ffa_emad_size_get() returns 16 bytes in that case
while reserved has an offset of 24.
Instead of zeroing fields, memset the struct to zero first based on
the FFA version.
2) Make sure there is enough size to write constituents.
While at it, convert the only sizeof() in the driver that uses a
type instead of variable.
Signed-off-by: Mostafa Saleh <smostafa@google•com>
---
drivers/firmware/arm_ffa/driver.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index eb2782848283..b700b2e93e72 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -697,11 +697,10 @@ ffa_setup_and_transmit(u32 func_id, void *buffer, u32 max_fragsize,
for (idx = 0; idx < args->nattrs; idx++) {
ep_mem_access = buffer +
ffa_mem_desc_offset(buffer, idx, drv_info->version);
+ memset(ep_mem_access, 0, ffa_emad_size_get(drv_info->version));
ep_mem_access->receiver = args->attrs[idx].receiver;
ep_mem_access->attrs = args->attrs[idx].attrs;
ep_mem_access->composite_off = composite_offset;
- ep_mem_access->flag = 0;
- ep_mem_access->reserved = 0;
ffa_emad_impdef_value_init(drv_info->version,
ep_mem_access->impdef_val,
args->attrs[idx].impdef_val);
@@ -741,7 +740,7 @@ ffa_setup_and_transmit(u32 func_id, void *buffer, u32 max_fragsize,
constituents = buffer;
}
- if ((void *)constituents - buffer > max_fragsize) {
+ if ((void *)constituents + sizeof(*constituents) - buffer > max_fragsize) {
pr_err("Memory Region Fragment > Tx Buffer size\n");
return -EFAULT;
}
@@ -750,7 +749,7 @@ ffa_setup_and_transmit(u32 func_id, void *buffer, u32 max_fragsize,
constituents->pg_cnt = args->sg->length / FFA_PAGE_SIZE;
constituents->reserved = 0;
constituents++;
- frag_len += sizeof(struct ffa_mem_region_addr_range);
+ frag_len += sizeof(*constituents);
} while ((args->sg = sg_next(args->sg)));
return ffa_transmit_fragment(func_id, addr, buf_sz, frag_len,
--
2.54.0.669.g59709faab0-goog
next prev parent reply other threads:[~2026-05-20 20:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-20 20:49 [PATCH v4 0/5] arm_ffa, KVM: Fix FF-A emad offset calculations Mostafa Saleh
2026-05-20 20:49 ` [PATCH v4 1/5] optee: ffa: Add NULL check in optee_ffa_lend_protmem Mostafa Saleh
2026-05-20 20:49 ` Mostafa Saleh [this message]
2026-05-21 12:51 ` [PATCH v4 2/5] firmware: arm_ffa: Fix out-of-bound writes in ffa_setup_and_transmit() Sudeep Holla
2026-05-20 20:49 ` [PATCH v4 3/5] firmware: arm_ffa: Fix Endpoint Memory Access Descriptor offset calculation Mostafa Saleh
2026-05-21 12:55 ` Sudeep Holla
2026-05-20 20:49 ` [PATCH v4 4/5] KVM: arm64: Fix bounds checking in do_ffa_mem_reclaim() Mostafa Saleh
2026-05-21 8:28 ` Marc Zyngier
2026-05-21 10:30 ` Mostafa Saleh
2026-05-21 10:43 ` Mostafa Saleh
2026-05-21 12:12 ` Marc Zyngier
2026-05-20 20:49 ` [PATCH v4 5/5] KVM: arm64: Validate the offset to the mem access descriptor Mostafa Saleh
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