[PATCH v2 perf-tools-next 5/6] perf trace beauty: Validate payload size in augmented sockaddr beautifier

[Aaron Tomlin <atomlin@atomlin.com>]

When pretty-printing augmented sockaddr arguments via
syscall_arg__scnprintf_augmented_sockaddr(), &arg->augmented.args->value
is cast to struct sockaddr without checking whether the captured payload
is large enough to hold the socket address.

If a malformed or truncated perf.data record provides an augmented
payload smaller than sizeof(sa->sa_family), accessing sa->sa_family or
dereferencing family-specific fields (e.g., struct sockaddr_in,
sockaddr_in6, or sockaddr_un) reads memory past the available buffer.

Validate that arg->augmented.size is at least sizeof(struct augmented_arg)
and that augmented_arg->size is at least sizeof(sa->sa_family) while
remaining within the available buffer. Furthermore, ensure that the
payload contains sufficient bytes for the given sa->sa_family before
invoking the family-specific formatter. If validation fails, fall back
to printing the raw pointer value.

Fixes: d5a7e6613b00 ("perf trace augmented_syscalls: Augment connect's 'sockaddr' arg")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
---
 tools/perf/trace/beauty/sockaddr.c | 35 +++++++++++++++++++++++++-----
 1 file changed, 30 insertions(+), 5 deletions(-)

diff --git a/tools/perf/trace/beauty/sockaddr.c b/tools/perf/trace/beauty/sockaddr.c
index a17a27ac2a6f..00c702ff4465 100644
--- a/tools/perf/trace/beauty/sockaddr.c
+++ b/tools/perf/trace/beauty/sockaddr.c
@@ -47,23 +47,48 @@ static size_t (*af_scnprintfs[])(struct sockaddr *sa, char *bf, size_t size) = {
 
 static size_t syscall_arg__scnprintf_augmented_sockaddr(struct syscall_arg *arg, char *bf, size_t size)
 {
-	struct sockaddr *sa = (struct sockaddr *)&arg->augmented.args->value;
+	struct augmented_arg *augmented_arg = arg->augmented.args;
+	struct sockaddr *sa;
 	char family[32];
 	size_t printed;
 
+	if (arg->augmented.size < (int)sizeof(*augmented_arg))
+		return 0;
+
+	if (augmented_arg->size < (int)sizeof(sa->sa_family) ||
+	    augmented_arg->size > arg->augmented.size - (int)sizeof(*augmented_arg))
+		return 0;
+
+	sa = (struct sockaddr *)&augmented_arg->value;
 	strarray__scnprintf(&strarray__socket_families, family, sizeof(family), "%d", arg->show_string_prefix, sa->sa_family);
 	printed = scnprintf(bf, size, "{ .family: %s", family);
 
-	if (sa->sa_family < ARRAY_SIZE(af_scnprintfs) && af_scnprintfs[sa->sa_family])
-		printed += af_scnprintfs[sa->sa_family](sa, bf + printed, size - printed);
+	if (sa->sa_family < ARRAY_SIZE(af_scnprintfs) && af_scnprintfs[sa->sa_family]) {
+		bool valid = false;
+
+		if (sa->sa_family == AF_INET && augmented_arg->size >= (int)sizeof(struct sockaddr_in))
+			valid = true;
+		else if (sa->sa_family == AF_INET6 && augmented_arg->size >= (int)sizeof(struct sockaddr_in6))
+			valid = true;
+		else if (sa->sa_family == AF_LOCAL &&
+			 augmented_arg->size > (int)offsetof(struct sockaddr_un, sun_path))
+			valid = true;
+
+		if (valid)
+			printed += af_scnprintfs[sa->sa_family](sa, bf + printed, size - printed);
+	}
 
 	return printed + scnprintf(bf + printed, size - printed, " }");
 }
 
 size_t syscall_arg__scnprintf_sockaddr(char *bf, size_t size, struct syscall_arg *arg)
 {
-	if (arg->augmented.args)
-		return syscall_arg__scnprintf_augmented_sockaddr(arg, bf, size);
+	if (arg->augmented.args) {
+		size_t printed = syscall_arg__scnprintf_augmented_sockaddr(arg, bf, size);
+
+		if (printed)
+			return printed;
+	}
 
 	return scnprintf(bf, size, "%#lx", arg->val);
 }
-- 
2.55.0