diff mbox series

[RFC,bpf-next,v4,4/6] bpf: Prevent BPF programs from access the buffer pointed by user_optval.

Message ID 20230819030143.419729-5-thinker.li@gmail.com (mailing list archive)
State RFC
Delegated to: BPF
Headers show
Series Sleepable BPF programs on cgroup {get,set}sockopt | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-PR pending PR summary
bpf/vmtest-bpf-next-VM_Test-1 success Logs for ShellCheck
bpf/vmtest-bpf-next-VM_Test-6 success Logs for set-matrix
bpf/vmtest-bpf-next-VM_Test-2 success Logs for build for aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-4 success Logs for build for x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-5 success Logs for build for x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-3 success Logs for build for s390x with gcc
bpf/vmtest-bpf-next-VM_Test-8 pending Logs for test_maps on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-7 success Logs for test_maps on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-9 success Logs for test_maps on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-10 success Logs for test_maps on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-18 success Logs for test_progs_no_alu32 on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-19 success Logs for test_progs_no_alu32_parallel on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-20 success Logs for test_progs_no_alu32_parallel on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-21 success Logs for test_progs_no_alu32_parallel on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-22 success Logs for test_progs_parallel on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-23 success Logs for test_progs_parallel on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-24 success Logs for test_progs_parallel on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-25 success Logs for test_verifier on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-27 success Logs for test_verifier on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-28 success Logs for test_verifier on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-29 success Logs for veristat
bpf/vmtest-bpf-next-VM_Test-11 success Logs for test_progs on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-13 success Logs for test_progs on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-14 success Logs for test_progs on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-15 success Logs for test_progs_no_alu32 on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-17 success Logs for test_progs_no_alu32 on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-26 success Logs for test_verifier on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-16 success Logs for test_progs_no_alu32 on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-12 success Logs for test_progs on s390x with gcc
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 73 this patch: 48
netdev/cc_maintainers warning 5 maintainers not CCed: daniel@iogearbox.net kpsingh@kernel.org john.fastabend@gmail.com jolsa@kernel.org haoluo@google.com
netdev/build_clang fail Errors and warnings before: 29 this patch: 29
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn fail Errors and warnings before: 80 this patch: 48
netdev/checkpatch warning WARNING: line length of 83 exceeds 80 columns WARNING: line length of 84 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 12 this patch: 12
netdev/source_inline success Was 0 now: 0

Commit Message

Kui-Feng Lee Aug. 19, 2023, 3:01 a.m. UTC 
From: Kui-Feng Lee <thinker.li@gmail.com>

Since the buffer pointed by ctx->optval can be in user space, BPF programs
in kernel space should not access it directly. They should use kfuncs
provided later to access data.

Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
---
 kernel/bpf/cgroup.c   | 16 ++++++-
 kernel/bpf/verifier.c | 98 +++++++++++++++++++++----------------------
 2 files changed, 63 insertions(+), 51 deletions(-)
diff mbox series

Patch

diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index b4f37960274d..1b2006dac4d5 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -2495,12 +2495,24 @@  static bool cg_sockopt_is_valid_access(int off, int size,
 	case offsetof(struct bpf_sockopt, optval):
 		if (size != sizeof(__u64))
 			return false;
-		info->reg_type = PTR_TO_PACKET;
+		if (prog->aux->sleepable)
+			/* Prohibit access to the memory pointed by optval
+			 * in sleepable programs.
+			 */
+			info->reg_type = PTR_TO_AUX | MEM_USER;
+		else
+			info->reg_type = PTR_TO_AUX;
 		break;
 	case offsetof(struct bpf_sockopt, optval_end):
 		if (size != sizeof(__u64))
 			return false;
-		info->reg_type = PTR_TO_PACKET_END;
+		if (prog->aux->sleepable)
+			/* Prohibit access to the memory pointed by
+			 * optval_end in sleepable programs.
+			 */
+			info->reg_type = PTR_TO_AUX_END | MEM_USER;
+		else
+			info->reg_type = PTR_TO_AUX_END;
 		break;
 	case offsetof(struct bpf_sockopt, retval):
 		if (size != size_default)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 05ab2c7f8798..83731e998b09 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -13403,7 +13403,7 @@  static void find_good_pkt_aux_pointers(struct bpf_verifier_state *vstate,
 	 * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16.
 	 */
 	bpf_for_each_reg_in_vstate(vstate, state, reg, ({
-		if (reg->type == type && reg->id == dst_reg->id)
+		if (base_type(reg->type) == type && reg->id == dst_reg->id)
 			/* keep the maximum range already checked */
 			reg->range = max(reg->range, new_range);
 	}));
@@ -13958,100 +13958,100 @@  static bool try_match_pkt_pointers(const struct bpf_insn *insn,
 
 	switch (BPF_OP(insn->code)) {
 	case BPF_JGT:
-		if ((dst_reg->type == PTR_TO_PACKET &&
-		     src_reg->type == PTR_TO_PACKET_END) ||
-		    (dst_reg->type == PTR_TO_AUX &&
-		     src_reg->type == PTR_TO_AUX_END) ||
-		    (dst_reg->type == PTR_TO_PACKET_META &&
+		if ((base_type(dst_reg->type) == PTR_TO_PACKET &&
+		     base_type(src_reg->type) == PTR_TO_PACKET_END) ||
+		    (base_type(dst_reg->type) == PTR_TO_AUX &&
+		     base_type(src_reg->type) == PTR_TO_AUX_END) ||
+		    (base_type(dst_reg->type) == PTR_TO_PACKET_META &&
 		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
 			/* pkt_data' > pkt_end, pkt_meta' > pkt_data */
 			find_good_pkt_aux_pointers(this_branch, dst_reg,
-						   dst_reg->type, false);
+						   base_type(dst_reg->type), false);
 			mark_pkt_aux_end(other_branch, insn->dst_reg, true);
-		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
-			    src_reg->type == PTR_TO_PACKET) ||
-			   (dst_reg->type == PTR_TO_AUX_END &&
-			    src_reg->type == PTR_TO_AUX) ||
+		} else if ((base_type(dst_reg->type) == PTR_TO_PACKET_END &&
+			    base_type(src_reg->type) == PTR_TO_PACKET) ||
+			   (base_type(dst_reg->type) == PTR_TO_AUX_END &&
+			    base_type(src_reg->type) == PTR_TO_AUX) ||
 			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
-			    src_reg->type == PTR_TO_PACKET_META)) {
+			    base_type(src_reg->type) == PTR_TO_PACKET_META)) {
 			/* pkt_end > pkt_data', pkt_data > pkt_meta' */
 			find_good_pkt_aux_pointers(other_branch, src_reg,
-						   src_reg->type, true);
+						   base_type(src_reg->type), true);
 			mark_pkt_aux_end(this_branch, insn->src_reg, false);
 		} else {
 			return false;
 		}
 		break;
 	case BPF_JLT:
-		if ((dst_reg->type == PTR_TO_PACKET &&
-		     src_reg->type == PTR_TO_PACKET_END) ||
-		    (dst_reg->type == PTR_TO_AUX &&
-		     src_reg->type == PTR_TO_AUX_END) ||
-		    (dst_reg->type == PTR_TO_PACKET_META &&
+		if ((base_type(dst_reg->type) == PTR_TO_PACKET &&
+		     base_type(src_reg->type) == PTR_TO_PACKET_END) ||
+		    (base_type(dst_reg->type) == PTR_TO_AUX &&
+		     base_type(src_reg->type) == PTR_TO_AUX_END) ||
+		    (base_type(dst_reg->type) == PTR_TO_PACKET_META &&
 		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
 			/* pkt_data' < pkt_end, pkt_meta' < pkt_data */
 			find_good_pkt_aux_pointers(other_branch, dst_reg,
-						   dst_reg->type, true);
+						   base_type(dst_reg->type), true);
 			mark_pkt_aux_end(this_branch, insn->dst_reg, false);
-		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
-			    src_reg->type == PTR_TO_PACKET) ||
-			   (dst_reg->type == PTR_TO_AUX_END &&
-			    src_reg->type == PTR_TO_AUX) ||
+		} else if ((base_type(dst_reg->type) == PTR_TO_PACKET_END &&
+			    base_type(src_reg->type) == PTR_TO_PACKET) ||
+			   (base_type(dst_reg->type) == PTR_TO_AUX_END &&
+			    base_type(src_reg->type) == PTR_TO_AUX) ||
 			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
-			    src_reg->type == PTR_TO_PACKET_META)) {
+			    base_type(src_reg->type) == PTR_TO_PACKET_META)) {
 			/* pkt_end < pkt_data', pkt_data > pkt_meta' */
 			find_good_pkt_aux_pointers(this_branch, src_reg,
-						   src_reg->type, false);
+						   base_type(src_reg->type), false);
 			mark_pkt_aux_end(other_branch, insn->src_reg, true);
 		} else {
 			return false;
 		}
 		break;
 	case BPF_JGE:
-		if ((dst_reg->type == PTR_TO_PACKET &&
-		     src_reg->type == PTR_TO_PACKET_END) ||
-		    (dst_reg->type == PTR_TO_AUX &&
-		     src_reg->type == PTR_TO_AUX_END) ||
-		    (dst_reg->type == PTR_TO_PACKET_META &&
+		if ((base_type(dst_reg->type) == PTR_TO_PACKET &&
+		     base_type(src_reg->type) == PTR_TO_PACKET_END) ||
+		    (base_type(dst_reg->type) == PTR_TO_AUX &&
+		     base_type(src_reg->type) == PTR_TO_AUX_END) ||
+		    (base_type(dst_reg->type) == PTR_TO_PACKET_META &&
 		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
 			/* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */
 			find_good_pkt_aux_pointers(this_branch, dst_reg,
-						   dst_reg->type, true);
+						   base_type(dst_reg->type), true);
 			mark_pkt_aux_end(other_branch, insn->dst_reg, false);
-		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
-			    src_reg->type == PTR_TO_PACKET) ||
-			   (dst_reg->type == PTR_TO_AUX_END &&
-			    src_reg->type == PTR_TO_AUX) ||
+		} else if ((base_type(dst_reg->type) == PTR_TO_PACKET_END &&
+			    base_type(src_reg->type) == PTR_TO_PACKET) ||
+			   (base_type(dst_reg->type) == PTR_TO_AUX_END &&
+			    base_type(src_reg->type) == PTR_TO_AUX) ||
 			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
-			    src_reg->type == PTR_TO_PACKET_META)) {
+			    base_type(src_reg->type) == PTR_TO_PACKET_META)) {
 			/* pkt_end >= pkt_data', pkt_data >= pkt_meta' */
 			find_good_pkt_aux_pointers(other_branch, src_reg,
-						   src_reg->type, false);
+						   base_type(src_reg->type), false);
 			mark_pkt_aux_end(this_branch, insn->src_reg, true);
 		} else {
 			return false;
 		}
 		break;
 	case BPF_JLE:
-		if ((dst_reg->type == PTR_TO_PACKET &&
-		     src_reg->type == PTR_TO_PACKET_END) ||
-		    (dst_reg->type == PTR_TO_AUX &&
-		     src_reg->type == PTR_TO_AUX_END) ||
-		    (dst_reg->type == PTR_TO_PACKET_META &&
+		if ((base_type(dst_reg->type) == PTR_TO_PACKET &&
+		     base_type(src_reg->type) == PTR_TO_PACKET_END) ||
+		    (base_type(dst_reg->type) == PTR_TO_AUX &&
+		     base_type(src_reg->type) == PTR_TO_AUX_END) ||
+		    (base_type(dst_reg->type) == PTR_TO_PACKET_META &&
 		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
 			/* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */
 			find_good_pkt_aux_pointers(other_branch, dst_reg,
-						   dst_reg->type, false);
+						   base_type(dst_reg->type), false);
 			mark_pkt_aux_end(this_branch, insn->dst_reg, true);
-		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
-			    src_reg->type == PTR_TO_PACKET) ||
-			   (dst_reg->type == PTR_TO_AUX_END &&
-			    src_reg->type == PTR_TO_AUX) ||
+		} else if ((base_type(dst_reg->type) == PTR_TO_PACKET_END &&
+			    base_type(src_reg->type) == PTR_TO_PACKET) ||
+			   (base_type(dst_reg->type) == PTR_TO_AUX_END &&
+			    base_type(src_reg->type) == PTR_TO_AUX) ||
 			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
-			    src_reg->type == PTR_TO_PACKET_META)) {
+			    base_type(src_reg->type) == PTR_TO_PACKET_META)) {
 			/* pkt_end <= pkt_data', pkt_data <= pkt_meta' */
 			find_good_pkt_aux_pointers(this_branch, src_reg,
-						   src_reg->type, true);
+						   base_type(src_reg->type), true);
 			mark_pkt_aux_end(other_branch, insn->src_reg, false);
 		} else {
 			return false;