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32 lines
1.5 KiB
32 lines
1.5 KiB
2 years ago
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commit 5b06f538c5aee0389ed034f60d90a8884d6d54de
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Author: Adam Maris <amaris@redhat.com>
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Date: Thu Mar 14 16:51:16 2019 -0400
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malloc: Check for large bin list corruption when inserting unsorted chunk
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Fixes bug 24216. This patch adds security checks for bk and bk_nextsize pointers
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of chunks in large bin when inserting chunk from unsorted bin. It was possible
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to write the pointer to victim (newly inserted chunk) to arbitrary memory
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locations if bk or bk_nextsize pointers of the next large bin chunk
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got corrupted.
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diff --git a/malloc/malloc.c b/malloc/malloc.c
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index 4412a4ffc83b013b..723d393f529bdb4c 100644
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--- a/malloc/malloc.c
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+++ b/malloc/malloc.c
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@@ -3876,10 +3876,14 @@ _int_malloc (mstate av, size_t bytes)
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{
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victim->fd_nextsize = fwd;
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victim->bk_nextsize = fwd->bk_nextsize;
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+ if (__glibc_unlikely (fwd->bk_nextsize->fd_nextsize != fwd))
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+ malloc_printerr ("malloc(): largebin double linked list corrupted (nextsize)");
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fwd->bk_nextsize = victim;
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victim->bk_nextsize->fd_nextsize = victim;
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}
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bck = fwd->bk;
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+ if (bck->fd != fwd)
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+ malloc_printerr ("malloc(): largebin double linked list corrupted (bk)");
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}
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}
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else
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