From 996d9a1d29d29a6744e1b8e9efac722fb2c5281c Mon Sep 17 00:00:00 2001 From: Zbigniew Jędrzejewski-Szmek Date: Apr 07 2021 22:35:37 +0000 Subject: bus-message: avoid an infinite loop on empty structures The alternative would be to treat gvariant and !gvariant messages differently. But this is a problem because we check signatures is variuos places before we have an actual message, for example in sd_bus_add_object_vtable(). It seems better to treat things consistent (i.e. follow the lowest common denominator) and disallow empty structures everywhere. (cherry picked from commit ec6bda56cbca9509b1abde1122645630caca877c) Resolves: #1696224 patch_name: 0162-bus-message-avoid-an-infinite-loop-on-empty-structur.patch present_in_specfile: true location_in_specfile: 162 squash_commits: true --- diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c index 7f87d01..1d06fcb 100644 --- a/src/libsystemd/sd-bus/bus-message.c +++ b/src/libsystemd/sd-bus/bus-message.c @@ -4178,6 +4178,7 @@ _public_ int sd_bus_message_peek_type(sd_bus_message *m, char *type, const char /* signature_element_length does verification internally */ + /* The array element must not be empty */ assert(l >= 1); if (free_and_strndup(&c->peeked_signature, c->signature + c->index + 1, l) < 0) @@ -4201,7 +4202,7 @@ _public_ int sd_bus_message_peek_type(sd_bus_message *m, char *type, const char if (r < 0) return r; - assert(l >= 2); + assert(l >= 3); if (free_and_strndup(&c->peeked_signature, c->signature + c->index + 1, l - 2) < 0) return -ENOMEM; diff --git a/src/libsystemd/sd-bus/bus-signature.c b/src/libsystemd/sd-bus/bus-signature.c index 18c91e8..1ca37cb 100644 --- a/src/libsystemd/sd-bus/bus-signature.c +++ b/src/libsystemd/sd-bus/bus-signature.c @@ -58,6 +58,12 @@ static int signature_element_length_internal( p += t; } + if (p - s < 2) + /* D-Bus spec: Empty structures are not allowed; there + * must be at least one type code between the parentheses. + */ + return -EINVAL; + *l = p - s + 1; return 0; } diff --git a/src/libsystemd/sd-bus/test-bus-gvariant.c b/src/libsystemd/sd-bus/test-bus-gvariant.c index 75804f3..e606970 100644 --- a/src/libsystemd/sd-bus/test-bus-gvariant.c +++ b/src/libsystemd/sd-bus/test-bus-gvariant.c @@ -19,7 +19,7 @@ static void test_bus_gvariant_is_fixed_size(void) { assert_se(bus_gvariant_is_fixed_size("") > 0); - assert_se(bus_gvariant_is_fixed_size("()") > 0); + assert_se(bus_gvariant_is_fixed_size("()") == -EINVAL); assert_se(bus_gvariant_is_fixed_size("y") > 0); assert_se(bus_gvariant_is_fixed_size("u") > 0); assert_se(bus_gvariant_is_fixed_size("b") > 0); @@ -44,7 +44,7 @@ static void test_bus_gvariant_is_fixed_size(void) { static void test_bus_gvariant_get_size(void) { assert_se(bus_gvariant_get_size("") == 0); - assert_se(bus_gvariant_get_size("()") == 1); + assert_se(bus_gvariant_get_size("()") == -EINVAL); assert_se(bus_gvariant_get_size("y") == 1); assert_se(bus_gvariant_get_size("u") == 4); assert_se(bus_gvariant_get_size("b") == 1); @@ -76,7 +76,7 @@ static void test_bus_gvariant_get_size(void) { static void test_bus_gvariant_get_alignment(void) { assert_se(bus_gvariant_get_alignment("") == 1); - assert_se(bus_gvariant_get_alignment("()") == 1); + assert_se(bus_gvariant_get_alignment("()") == -EINVAL); assert_se(bus_gvariant_get_alignment("y") == 1); assert_se(bus_gvariant_get_alignment("b") == 1); assert_se(bus_gvariant_get_alignment("u") == 4); diff --git a/src/libsystemd/sd-bus/test-bus-marshal.c b/src/libsystemd/sd-bus/test-bus-marshal.c index f007168..1743b1b 100644 --- a/src/libsystemd/sd-bus/test-bus-marshal.c +++ b/src/libsystemd/sd-bus/test-bus-marshal.c @@ -151,7 +151,7 @@ int main(int argc, char *argv[]) { assert_se(r >= 0); r = sd_bus_message_append(m, "()"); - assert_se(r >= 0); + assert_se(r == -EINVAL); r = sd_bus_message_append(m, "ba(ss)", 255, 3, "aaa", "1", "bbb", "2", "ccc", "3"); assert_se(r >= 0); @@ -293,7 +293,7 @@ int main(int argc, char *argv[]) { assert_se(v == 10); r = sd_bus_message_read(m, "()"); - assert_se(r > 0); + assert_se(r < 0); r = sd_bus_message_read(m, "ba(ss)", &boolean, 3, &x, &y, &a, &b, &c, &d); assert_se(r > 0); @@ -374,7 +374,7 @@ int main(int argc, char *argv[]) { assert_se(sd_bus_message_verify_type(m, 'a', "{yv}") > 0); - r = sd_bus_message_skip(m, "a{yv}y(ty)y(yt)y()"); + r = sd_bus_message_skip(m, "a{yv}y(ty)y(yt)y"); assert_se(r >= 0); assert_se(sd_bus_message_verify_type(m, 'b', NULL) > 0); diff --git a/src/libsystemd/sd-bus/test-bus-signature.c b/src/libsystemd/sd-bus/test-bus-signature.c index 1ba1909..a716cd1 100644 --- a/src/libsystemd/sd-bus/test-bus-signature.c +++ b/src/libsystemd/sd-bus/test-bus-signature.c @@ -16,9 +16,9 @@ int main(int argc, char *argv[]) { assert_se(signature_is_single("v", false)); assert_se(signature_is_single("as", false)); assert_se(signature_is_single("(ss)", false)); - assert_se(signature_is_single("()", false)); - assert_se(signature_is_single("(()()()()())", false)); - assert_se(signature_is_single("(((())))", false)); + assert_se(!signature_is_single("()", false)); + assert_se(!signature_is_single("(()()()()())", false)); + assert_se(!signature_is_single("(((())))", false)); assert_se(signature_is_single("((((s))))", false)); assert_se(signature_is_single("{ss}", true)); assert_se(signature_is_single("a{ss}", false)); @@ -63,7 +63,7 @@ int main(int argc, char *argv[]) { assert_se(signature_is_valid("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaas", false)); assert_se(!signature_is_valid("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaau", false)); - assert_se(signature_is_valid("(((((((((((((((((((((((((((((((())))))))))))))))))))))))))))))))", false)); + assert_se(signature_is_valid("((((((((((((((((((((((((((((((((s))))))))))))))))))))))))))))))))", false)); assert_se(!signature_is_valid("((((((((((((((((((((((((((((((((()))))))))))))))))))))))))))))))))", false)); assert_se(namespace_complex_pattern("", "")); diff --git a/test/fuzz/fuzz-bus-message/crash-26bba7182dedc8848939931d9fcefcb7922f2e56 b/test/fuzz/fuzz-bus-message/crash-26bba7182dedc8848939931d9fcefcb7922f2e56 new file mode 100644 index 0000000..f1bf322 Binary files /dev/null and b/test/fuzz/fuzz-bus-message/crash-26bba7182dedc8848939931d9fcefcb7922f2e56 differ diff --git a/test/fuzz/fuzz-bus-message/timeout-08ee8f6446a4064db064e8e0b3d220147f7d0b5b b/test/fuzz/fuzz-bus-message/timeout-08ee8f6446a4064db064e8e0b3d220147f7d0b5b new file mode 100644 index 0000000..c975f90 Binary files /dev/null and b/test/fuzz/fuzz-bus-message/timeout-08ee8f6446a4064db064e8e0b3d220147f7d0b5b differ