Prevent the pKVM hypervisor from making assumptions that the endpoint memory access descriptor (EMAD) comes right after the FF-A memory region header. Prior to FF-A version 1.1 the header of the memory region didn't contain an offset to the endpoint memory access descriptor. The layout of a memory transaction looks like this from 1.1 onward: Type | Field name | Offset [ Header | ffa_mem_region | 0 EMAD 1 | ffa_mem_region_attributes) | ffa_mem_region.ep_mem_offset ] Verify that the offset to the first endpoint memory access descriptor is within the mailbox buffer bounds.
Also, fix one hardcoded sizeof(struct ffa_mem_region_attributes) that should be replaced ffa_emad_size_get() for compatibility with FFA v1.0.
Fixes: 42fb33dde42b ("KVM: arm64: Use FF-A 1.1 with pKVM") Signed-off-by: Mostafa Saleh smostafa@google.com Signed-off-by: Sebastian Ene sebastianene@google.com --- arch/arm64/kvm/hyp/nvhe/ffa.c | 27 +++++++++++++++++++-------- include/linux/arm_ffa.h | 7 +++++++ 2 files changed, 26 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c index 41cc4c1bafeb..2e7ab7e3319d 100644 --- a/arch/arm64/kvm/hyp/nvhe/ffa.c +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c @@ -476,11 +476,12 @@ static void __do_ffa_mem_xfer(const u64 func_id, DECLARE_REG(u32, fraglen, ctxt, 2); DECLARE_REG(u64, addr_mbz, ctxt, 3); DECLARE_REG(u32, npages_mbz, ctxt, 4); + u32 offset, nr_ranges, checked_offset, em_mem_access_off; struct ffa_mem_region_attributes *ep_mem_access; struct ffa_composite_mem_region *reg; struct ffa_mem_region *buf; - u32 offset, nr_ranges, checked_offset; int ret = 0; + size_t mem_region_len = FFA_MEM_REGION_SZ(hyp_ffa_version);
if (addr_mbz || npages_mbz || fraglen > len || fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE) { @@ -488,8 +489,7 @@ static void __do_ffa_mem_xfer(const u64 func_id, goto out; }
- if (fraglen < sizeof(struct ffa_mem_region) + - sizeof(struct ffa_mem_region_attributes)) { + if (fraglen < mem_region_len + ffa_emad_size_get(hyp_ffa_version)) { ret = FFA_RET_INVALID_PARAMETERS; goto out; } @@ -508,8 +508,13 @@ static void __do_ffa_mem_xfer(const u64 func_id, buf = hyp_buffers.tx; memcpy(buf, host_buffers.tx, fraglen);
- ep_mem_access = (void *)buf + - ffa_mem_desc_offset(buf, 0, hyp_ffa_version); + em_mem_access_off = ffa_mem_desc_offset(buf, 0, hyp_ffa_version); + if ((u64)em_mem_access_off + ffa_emad_size_get(hyp_ffa_version) > fraglen) { + ret = FFA_RET_INVALID_PARAMETERS; + goto out_unlock; + } + + ep_mem_access = (void *)buf + em_mem_access_off; offset = ep_mem_access->composite_off; if (!offset || buf->ep_count != 1 || buf->sender_id != HOST_FFA_ID) { ret = FFA_RET_INVALID_PARAMETERS; @@ -574,9 +579,9 @@ static void do_ffa_mem_reclaim(struct arm_smccc_1_2_regs *res, DECLARE_REG(u32, handle_lo, ctxt, 1); DECLARE_REG(u32, handle_hi, ctxt, 2); DECLARE_REG(u32, flags, ctxt, 3); + u32 offset, len, fraglen, fragoff, em_mem_access_off; struct ffa_mem_region_attributes *ep_mem_access; struct ffa_composite_mem_region *reg; - u32 offset, len, fraglen, fragoff; struct ffa_mem_region *buf; int ret = 0; u64 handle; @@ -599,8 +604,14 @@ static void do_ffa_mem_reclaim(struct arm_smccc_1_2_regs *res, len = res->a1; fraglen = res->a2;
- ep_mem_access = (void *)buf + - ffa_mem_desc_offset(buf, 0, hyp_ffa_version); + em_mem_access_off = ffa_mem_desc_offset(buf, 0, hyp_ffa_version); + if ((u64)em_mem_access_off + ffa_emad_size_get(hyp_ffa_version) > fraglen) { + ret = FFA_RET_INVALID_PARAMETERS; + ffa_rx_release(res); + goto out_unlock; + } + + ep_mem_access = (void *)buf + em_mem_access_off; offset = ep_mem_access->composite_off; /* * We can trust the SPMD to get this right, but let's at least diff --git a/include/linux/arm_ffa.h b/include/linux/arm_ffa.h index 033c630b271b..e71d83ee0aef 100644 --- a/include/linux/arm_ffa.h +++ b/include/linux/arm_ffa.h @@ -421,6 +421,13 @@ struct ffa_mem_region { #define FFA_EMAD_HAS_IMPDEF_FIELD(version) ((version) >= FFA_VERSION_1_2) #define FFA_MEM_REGION_HAS_EP_MEM_OFFSET(version) ((version) > FFA_VERSION_1_0)
+/* The layout changed from FFA_VERSION_1_0 and the region includes an + * ep_mem_offset. + */ +#define FFA_MEM_REGION_SZ(version) (!FFA_MEM_REGION_HAS_EP_MEM_OFFSET((version)) ?\ + offsetof(struct ffa_mem_region, ep_mem_offset) :\ + sizeof(struct ffa_mem_region)) + static inline u32 ffa_emad_size_get(u32 ffa_version) { u32 sz;