61 lines
2.2 KiB
Diff
61 lines
2.2 KiB
Diff
From 17de4d15687aa30c49660dc4b792b1fb4d38b569 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>
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Date: Thu, 7 Apr 2022 17:29:54 +0200
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Subject: [PATCH 6/8] Fix CVE-2022-24795
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There was an integer overflow in yajl_buf_ensure_available() leading
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to allocating less memory than requested. Then data were written past
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the allocated heap buffer in yajl_buf_append(), the only caller of
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yajl_buf_ensure_available(). Another result of the overflow was an
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infinite loop without a return from yajl_buf_ensure_available().
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yajl-ruby project, which bundles yajl, fixed it
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<https://github.com/brianmario/yajl-ruby/pull/211> by checking for the
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integer overflow, fortifying buffer allocations, and report the
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failures to a caller. But then the caller yajl_buf_append() skips
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a memory write if yajl_buf_ensure_available() failed leading to a data
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corruption.
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A yajl fork mainter recommended calling memory allocation callbacks with
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the large memory request and let them to handle it. But that has the
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problem that it's not possible pass the overely large size to the
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callbacks.
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This patch catches the integer overflow and terminates the process
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with abort().
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https://github.com/lloyd/yajl/issues/239
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https://github.com/brianmario/yajl-ruby/security/advisories/GHSA-jj47-x69x-mxrm
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(cherry picked from commit 23cea2d7677e396efed78bbf1bf153961fab6bad
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in https://github.com/ppisar/yajl)
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---
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src/yajl_buf.c | 12 +++++++++++-
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1 file changed, 11 insertions(+), 1 deletion(-)
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diff --git a/src/yajl_buf.c b/src/yajl_buf.c
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index 1aeafde..55c11ad 100644
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--- a/src/yajl_buf.c
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+++ b/src/yajl_buf.c
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@@ -45,7 +45,17 @@ void yajl_buf_ensure_available(yajl_buf buf, size_t want)
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need = buf->len;
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- while (want >= (need - buf->used)) need <<= 1;
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+ if (((buf->used > want) ? buf->used : want) > (size_t)(buf->used + want)) {
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+ /* We cannot allocate more memory than SIZE_MAX. */
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+ abort();
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+ }
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+ while (want >= (need - buf->used)) {
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+ if (need >= (size_t)((size_t)(-1)<<1)>>1) {
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+ /* need would overflow. */
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+ abort();
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+ }
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+ need <<= 1;
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+ }
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if (need != buf->len) {
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buf->data = (unsigned char *) YA_REALLOC(buf->alloc, buf->data, need);
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--
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2.41.0
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