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| author | Jason Merrill <jason@redhat.com> | 2021-12-10 11:21:50 -0500 |
|---|---|---|
| committer | Jason Merrill <jason@redhat.com> | 2021-12-10 23:58:13 -0500 |
| commit | 2e8067041d1d69da02bd7578f58abc11eb35a04b (patch) | |
| tree | 5b3b28b4f30f602d6f8e96592a560f9803b3e08d | |
| parent | 0bceef1671adee52e9cc409d82e5f5590fed8d45 (diff) | |
| download | gcc-2e8067041d1d69da02bd7578f58abc11eb35a04b.zip gcc-2e8067041d1d69da02bd7578f58abc11eb35a04b.tar.gz gcc-2e8067041d1d69da02bd7578f58abc11eb35a04b.tar.bz2 | |
libstdc++: check length in string append [PR103534]
In the testcase for 103534 we get a warning about append leading to memcpy
of a very large number of bytes overflowing the buffer. This turns out to
be because we weren't calling _M_check_length for string append. Rather
than do that directly, let's go through the public pointer append that calls
it.
PR c++/103534
libstdc++-v3/ChangeLog:
* include/bits/basic_string.h (append (basic_string)): Call pointer
append instead of _M_append directly.
gcc/testsuite/ChangeLog:
* g++.dg/warn/Wstringop-overflow-8.C: New test.
| -rw-r--r-- | gcc/testsuite/g++.dg/warn/Wstringop-overflow-8.C | 10 | ||||
| -rw-r--r-- | libstdc++-v3/include/bits/basic_string.h | 8 |
2 files changed, 14 insertions, 4 deletions
diff --git a/gcc/testsuite/g++.dg/warn/Wstringop-overflow-8.C b/gcc/testsuite/g++.dg/warn/Wstringop-overflow-8.C new file mode 100644 index 0000000..d0ef5e7 --- /dev/null +++ b/gcc/testsuite/g++.dg/warn/Wstringop-overflow-8.C @@ -0,0 +1,10 @@ +// PR c++/103534 +// { dg-additional-options "-O -Wall" } + +#include <string> + +std::string foo(std::string x) +{ + // This used to get a bogus -Wstringop-overflow warning. + return std::string("1234567890123456") + x; +} diff --git a/libstdc++-v3/include/bits/basic_string.h b/libstdc++-v3/include/bits/basic_string.h index 4007a8d..3da2f80 100644 --- a/libstdc++-v3/include/bits/basic_string.h +++ b/libstdc++-v3/include/bits/basic_string.h @@ -1382,7 +1382,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11 _GLIBCXX20_CONSTEXPR basic_string& append(const basic_string& __str) - { return _M_append(__str._M_data(), __str.size()); } + { return this->append(__str._M_data(), __str.size()); } /** * @brief Append a substring. @@ -1400,9 +1400,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11 _GLIBCXX20_CONSTEXPR basic_string& append(const basic_string& __str, size_type __pos, size_type __n = npos) - { return _M_append(__str._M_data() - + __str._M_check(__pos, "basic_string::append"), - __str._M_limit(__pos, __n)); } + { return this->append(__str._M_data() + + __str._M_check(__pos, "basic_string::append"), + __str._M_limit(__pos, __n)); } /** * @brief Append a C substring. |