From 744ea4e3885eccb6d332a06fae9eb7420a622c0f Mon Sep 17 00:00:00 2001 From: Gilad Reti Date: Wed, 13 Jan 2021 07:38:07 +0200 Subject: bpf: Support PTR_TO_MEM{,_OR_NULL} register spilling Add support for pointer to mem register spilling, to allow the verifier to track pointers to valid memory addresses. Such pointers are returned for example by a successful call of the bpf_ringbuf_reserve helper. The patch was partially contributed by CyberArk Software, Inc. Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it") Suggested-by: Yonghong Song Signed-off-by: Gilad Reti Signed-off-by: Alexei Starovoitov Acked-by: KP Singh Link: https://lore.kernel.org/bpf/20210113053810.13518-1-gilad.reti@gmail.com --- kernel/bpf/verifier.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/bpf/verifier.c') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 17270b8404f1..36af69fac591 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2217,6 +2217,8 @@ static bool is_spillable_regtype(enum bpf_reg_type type) case PTR_TO_RDWR_BUF: case PTR_TO_RDWR_BUF_OR_NULL: case PTR_TO_PERCPU_BTF_ID: + case PTR_TO_MEM: + case PTR_TO_MEM_OR_NULL: return true; default: return false; -- cgit v1.2.3 From bc895e8b2a64e502fbba72748d59618272052a8b Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 20 Jan 2021 00:24:24 +0100 Subject: bpf: Fix signed_{sub,add32}_overflows type handling Fix incorrect signed_{sub,add32}_overflows() input types (and a related buggy comment). It looks like this might have slipped in via copy/paste issue, also given prior to 3f50f132d840 ("bpf: Verifier, do explicit ALU32 bounds tracking") the signature of signed_sub_overflows() had s64 a and s64 b as its input args whereas now they are truncated to s32. Thus restore proper types. Also, the case of signed_add32_overflows() is not consistent to signed_sub32_overflows(). Both have s32 as inputs, therefore align the former. Fixes: 3f50f132d840 ("bpf: Verifier, do explicit ALU32 bounds tracking") Reported-by: De4dCr0w Signed-off-by: Daniel Borkmann Reviewed-by: John Fastabend Acked-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/bpf/verifier.c') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 36af69fac591..e7368c5eacb7 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5313,7 +5313,7 @@ static bool signed_add_overflows(s64 a, s64 b) return res < a; } -static bool signed_add32_overflows(s64 a, s64 b) +static bool signed_add32_overflows(s32 a, s32 b) { /* Do the add in u32, where overflow is well-defined */ s32 res = (s32)((u32)a + (u32)b); @@ -5323,7 +5323,7 @@ static bool signed_add32_overflows(s64 a, s64 b) return res < a; } -static bool signed_sub_overflows(s32 a, s32 b) +static bool signed_sub_overflows(s64 a, s64 b) { /* Do the sub in u64, where overflow is well-defined */ s64 res = (s64)((u64)a - (u64)b); @@ -5335,7 +5335,7 @@ static bool signed_sub_overflows(s32 a, s32 b) static bool signed_sub32_overflows(s32 a, s32 b) { - /* Do the sub in u64, where overflow is well-defined */ + /* Do the sub in u32, where overflow is well-defined */ s32 res = (s32)((u32)a - (u32)b); if (b < 0) -- cgit v1.2.3