Merge tag 'seccomp-v4.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into ra-next

- fix function prototype documentation
- fix samples to include NNP setting
- fix samples to avoid rule truncation
- fix samples hostprogs variable in Makefile

kernel/seccomp.c

@@ -41,8 +41,7 @@
  *         outside of a lifetime-guarded section.  In general, this
  *         is only needed for handling filters shared across tasks.
  * @prev: points to a previously installed, or inherited, filter
- * @len: the number of instructions in the program
- * @insnsi: the BPF program instructions to evaluate
+ * @prog: the BPF program to evaluate
  *
  * seccomp_filter objects are organized in a tree linked via the @prev
  * pointer.  For any task, it appears to be a singly-linked list starting
@@ -168,8 +167,8 @@ static int seccomp_check_filter(struct sock_filter *filter, unsigned int flen)
 }
 
 /**
- * seccomp_run_filters - evaluates all seccomp filters against @syscall
- * @syscall: number of the current system call
+ * seccomp_run_filters - evaluates all seccomp filters against @sd
+ * @sd: optional seccomp data to be passed to filters
  *
  * Returns valid seccomp BPF response codes.
  */

samples/seccomp/Makefile

@@ -36,13 +36,13 @@ HOSTLOADLIBES_bpf-direct += $(MFLAG)
 HOSTLOADLIBES_bpf-fancy += $(MFLAG)
 HOSTLOADLIBES_dropper += $(MFLAG)
 endif
-always := $(hostprogs-y)
+always := $(hostprogs-m)
 else
 # MIPS system calls are defined based on the -mabi that is passed
 # to the toolchain which may or may not be a valid option
 # for the host toolchain. So disable tests if target architecture
 # is MIPS but the host isn't.
 ifndef CONFIG_MIPS
-always := $(hostprogs-y)
+always := $(hostprogs-m)
 endif
 endif

samples/seccomp/bpf-helper.c

@@ -18,41 +18,41 @@
 int bpf_resolve_jumps(struct bpf_labels *labels,
 		      struct sock_filter *filter, size_t count)
 {
-	struct sock_filter *begin = filter;
-	__u8 insn = count - 1;
+	size_t i;
 
-	if (count < 1)
+	if (count < 1 || count > BPF_MAXINSNS)
 		return -1;
 	/*
 	* Walk it once, backwards, to build the label table and do fixups.
 	* Since backward jumps are disallowed by BPF, this is easy.
 	*/
-	filter += insn;
-	for (; filter >= begin; --insn, --filter) {
-		if (filter->code != (BPF_JMP+BPF_JA))
+	for (i = 0; i < count; ++i) {
+		size_t offset = count - i - 1;
+		struct sock_filter *instr = &filter[offset];
+		if (instr->code != (BPF_JMP+BPF_JA))
 			continue;
-		switch ((filter->jt<<8)|filter->jf) {
+		switch ((instr->jt<<8)|instr->jf) {
 		case (JUMP_JT<<8)|JUMP_JF:
-			if (labels->labels[filter->k].location == 0xffffffff) {
+			if (labels->labels[instr->k].location == 0xffffffff) {
 				fprintf(stderr, "Unresolved label: '%s'\n",
-					labels->labels[filter->k].label);
+					labels->labels[instr->k].label);
 				return 1;
 			}
-			filter->k = labels->labels[filter->k].location -
-				    (insn + 1);
-			filter->jt = 0;
-			filter->jf = 0;
+			instr->k = labels->labels[instr->k].location -
+				    (offset + 1);
+			instr->jt = 0;
+			instr->jf = 0;
 			continue;
 		case (LABEL_JT<<8)|LABEL_JF:
-			if (labels->labels[filter->k].location != 0xffffffff) {
+			if (labels->labels[instr->k].location != 0xffffffff) {
 				fprintf(stderr, "Duplicate label use: '%s'\n",
-					labels->labels[filter->k].label);
+					labels->labels[instr->k].label);
 				return 1;
 			}
-			labels->labels[filter->k].location = insn;
-			filter->k = 0; /* fall through */
-			filter->jt = 0;
-			filter->jf = 0;
+			labels->labels[instr->k].location = offset;
+			instr->k = 0; /* fall through */
+			instr->jt = 0;
+			instr->jf = 0;
 			continue;
 		}
 	}

samples/seccomp/dropper.c

@@ -11,7 +11,6 @@
  * When run, returns the specified errno for the specified
  * system call number against the given architecture.
  *
- * Run this one as root as PR_SET_NO_NEW_PRIVS is not called.
  */
 
 #include <errno.h>
@@ -42,8 +41,12 @@ static int install_filter(int nr, int arch, int error)
 		.len = (unsigned short)(sizeof(filter)/sizeof(filter[0])),
 		.filter = filter,
 	};
+	if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
+		perror("prctl(NO_NEW_PRIVS)");
+		return 1;
+	}
 	if (prctl(PR_SET_SECCOMP, 2, &prog)) {
-		perror("prctl");
+		perror("prctl(PR_SET_SECCOMP)");
 		return 1;
 	}
 	return 0;