From f88214cf9d66c93f4d22c4c8980de9ee3ff45bab Mon Sep 17 00:00:00 2001 From: =?utf8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= Date: Fri, 3 Aug 2018 14:46:57 +0200 Subject: [PATCH] bus-message: fix calculation of offsets table for arrays This is similar to the grandparent commit 'fix calculation of offsets table', except that now the change is for array elements. Same story as before: we need to make sure that the offsets increase enough taking alignment into account. While at it, rename 'p' to 'previous' to match similar code in other places. --- src/libsystemd/sd-bus/bus-message.c | 17 ++++++++++++----- ...sh-d8f3941c74219b4c03532c9b244d5ea539c61af5 | Bin 0 -> 41 bytes 2 files changed, 12 insertions(+), 5 deletions(-) create mode 100644 test/fuzz/fuzz-bus-message/crash-d8f3941c74219b4c03532c9b244d5ea539c61af5 diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c index 11b050a24dd..f544ec13ce1 100644 --- a/src/libsystemd/sd-bus/bus-message.c +++ b/src/libsystemd/sd-bus/bus-message.c @@ -3507,7 +3507,7 @@ static int bus_message_enter_array( size_t rindex; void *q; - int r, alignment; + int r; assert(m); assert(c); @@ -3533,6 +3533,7 @@ static int bus_message_enter_array( if (!BUS_MESSAGE_IS_GVARIANT(m)) { /* dbus1 */ + int alignment; r = message_peek_body(m, &rindex, 4, 4, &q); if (r < 0) @@ -3566,7 +3567,8 @@ static int bus_message_enter_array( *n_offsets = 0; } else { - size_t where, p = 0, framing, sz; + size_t where, previous = 0, framing, sz; + int alignment; unsigned i; /* gvariant: variable length array */ @@ -3594,17 +3596,22 @@ static int bus_message_enter_array( if (!*offsets) return -ENOMEM; + alignment = bus_gvariant_get_alignment(c->signature); + assert(alignment > 0); + for (i = 0; i < *n_offsets; i++) { - size_t x; + size_t x, start; + + start = ALIGN_TO(previous, alignment); x = bus_gvariant_read_word_le((uint8_t*) q + i * sz, sz); if (x > c->item_size - sz) return -EBADMSG; - if (x < p) + if (x < start) return -EBADMSG; (*offsets)[i] = rindex + x; - p = x; + previous = x; } *item_size = (*offsets)[0] - rindex; diff --git a/test/fuzz/fuzz-bus-message/crash-d8f3941c74219b4c03532c9b244d5ea539c61af5 b/test/fuzz/fuzz-bus-message/crash-d8f3941c74219b4c03532c9b244d5ea539c61af5 new file mode 100644 index 0000000000000000000000000000000000000000..26262e1149825a114a89bf9cee5aeca0be463984 GIT binary patch literal 41 oc-qVP|DTC5gMmSS0SHWtIT#ojz<`m7fk7iNF)=d{1Tr)Q0Gy)-lK=n! literal 0 Hc-jL100001 -- 2.47.3