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| author | Tom Tromey <tom@tromey.com> | 2018-07-29 17:16:03 -0600 |
|---|---|---|
| committer | Tom Tromey <tom@tromey.com> | 2018-10-03 15:19:06 -0600 |
| commit | 0101665f864383147448c5871a67286a3f7a9a28 (patch) | |
| tree | dd4ce1e0693c6756fd37ca693294abf8dc7fca1b | |
| parent | ad69edbb4b230582ecd1863e68d0c2044f5ad901 (diff) | |
| download | gdb-0101665f864383147448c5871a67286a3f7a9a28.zip gdb-0101665f864383147448c5871a67286a3f7a9a28.tar.gz gdb-0101665f864383147448c5871a67286a3f7a9a28.tar.bz2 | |
Avoid undefined behavior in extract_integer
-fsanitize=undefined showed that extract_integer could left-shift a
negative value, which is undefined. This patch fixes the problem by
doing all the work in an unsigned type. This relies on
implementation-defined behavior, but I tend to think we are on safe
ground there. (Also, if need be, violations of this could probably be
detected, either by configure or by a static_assert.)
gdb/ChangeLog
2018-10-03 Tom Tromey <tom@tromey.com>
* findvar.c (extract_integer): Do work in an unsigned type.
| -rw-r--r-- | gdb/ChangeLog | 4 | ||||
| -rw-r--r-- | gdb/findvar.c | 2 |
2 files changed, 5 insertions, 1 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 36c4493..5787d44 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,9 @@ 2018-10-03 Tom Tromey <tom@tromey.com> + * findvar.c (extract_integer): Do work in an unsigned type. + +2018-10-03 Tom Tromey <tom@tromey.com> + * common/enum-flags.h (enum_flags::operator~): Add static assert. * symfile-add-flags.h (enum symfile_add_flag): Use unsigned as base type. diff --git a/gdb/findvar.c b/gdb/findvar.c index 9256833..be6c9d6 100644 --- a/gdb/findvar.c +++ b/gdb/findvar.c @@ -50,7 +50,7 @@ template<typename T, typename> T extract_integer (const gdb_byte *addr, int len, enum bfd_endian byte_order) { - T retval = 0; + typename std::make_unsigned<T>::type retval = 0; const unsigned char *p; const unsigned char *startaddr = addr; const unsigned char *endaddr = startaddr + len; |