ac3115d8ac
About undefined shift and integer overflow issues (cherry picked from commit 30b34d883dc099fbe68fe522bedbacc09c74eda6)
66 lines
1.8 KiB
Diff
66 lines
1.8 KiB
Diff
From 7b54caddca1013d10219da097e08d4cd4db6b923 Mon Sep 17 00:00:00 2001
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From: Alan Modra <amodra@gmail.com>
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Date: Tue, 16 Feb 2021 19:27:24 +1030
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Subject: [PATCH] ubsan: shift exponent is too large
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Reference: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=7b54caddca1013d10219da097e08d4cd4db6b923
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* libbfd.c (_bfd_read_unsigned_leb128): Avoid excessive shift.
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(_bfd_safe_read_leb128, _bfd_read_signed_leb128): Likewise.
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---
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bfd/ChangeLog | 5 +++++
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bfd/libbfd.c | 23 +++++++++++++++--------
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2 files changed, 20 insertions(+), 8 deletions(-)
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diff --git a/bfd/libbfd.c b/bfd/libbfd.c
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index cd94b81bc43..4f3dd5ad53c 100644
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--- a/bfd/libbfd.c
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+++ b/bfd/libbfd.c
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@@ -1074,8 +1074,11 @@ _bfd_read_unsigned_leb128 (bfd *abfd ATTRIBUTE_UNUSED,
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byte = bfd_get_8 (abfd, buf);
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buf++;
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num_read++;
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- result |= (((bfd_vma) byte & 0x7f) << shift);
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- shift += 7;
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+ if (shift < 8 * sizeof (result))
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+ {
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+ result |= (((bfd_vma) byte & 0x7f) << shift);
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+ shift += 7;
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+ }
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}
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while (byte & 0x80);
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*bytes_read_ptr = num_read;
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@@ -1104,10 +1107,11 @@ _bfd_safe_read_leb128 (bfd *abfd ATTRIBUTE_UNUSED,
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byte = bfd_get_8 (abfd, data);
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data++;
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num_read++;
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-
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- result |= ((bfd_vma) (byte & 0x7f)) << shift;
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-
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- shift += 7;
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+ if (shift < 8 * sizeof (result))
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+ {
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+ result |= ((bfd_vma) (byte & 0x7f)) << shift;
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+ shift += 7;
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+ }
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if ((byte & 0x80) == 0)
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break;
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}
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@@ -1141,8 +1145,11 @@ _bfd_read_signed_leb128 (bfd *abfd ATTRIBUTE_UNUSED,
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byte = bfd_get_8 (abfd, buf);
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buf ++;
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num_read ++;
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- result |= (((bfd_vma) byte & 0x7f) << shift);
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- shift += 7;
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+ if (shift < 8 * sizeof (result))
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+ {
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+ result |= (((bfd_vma) byte & 0x7f) << shift);
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+ shift += 7;
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+ }
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}
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while (byte & 0x80);
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if (shift < 8 * sizeof (result) && (byte & 0x40))
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--
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2.19.1
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