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| author | teor (Tim Wilson-Brown) <teor2345@gmail.com> | 2016-01-19 11:22:58 +1100 |
|---|---|---|
| committer | Nick Mathewson <nickm@torproject.org> | 2017-02-07 08:33:39 -0500 |
| commit | fb7d1f41b409761be3381efaeec0f56d2a470a9f (patch) | |
| tree | bcd8576bcd121b24fbb1298221159a25b4232b72 | |
| parent | 053e11f397f3f890c52a1add6aa4e75a9178eba0 (diff) | |
| download | tor-fb7d1f41b409761be3381efaeec0f56d2a470a9f.tar.gz tor-fb7d1f41b409761be3381efaeec0f56d2a470a9f.zip | |
Make memwipe() do nothing when passed a NULL pointer or zero size
Check size argument to memwipe() for underflow.
Closes bug #18089. Reported by "gk", patch by "teor".
Bugfix on 0.2.3.25 and 0.2.4.6-alpha (#7352),
commit 49dd5ef3 on 7 Nov 2012.
| -rw-r--r-- | changes/bug18089 | 6 | ||||
| -rw-r--r-- | src/common/crypto.c | 8 |
2 files changed, 14 insertions, 0 deletions
diff --git a/changes/bug18089 b/changes/bug18089 new file mode 100644 index 0000000000..c1fb342f77 --- /dev/null +++ b/changes/bug18089 @@ -0,0 +1,6 @@ + o Minor fixes (security): + - Make memwipe() do nothing when passed a NULL pointer + or zero size. Check size argument to memwipe() for underflow. + Closes bug #18089. Reported by "gk", patch by "teor". + Bugfix on 0.2.3.25 and 0.2.4.6-alpha (#7352), + commit 49dd5ef3 on 7 Nov 2012. diff --git a/src/common/crypto.c b/src/common/crypto.c index 925beb3529..f91391780a 100644 --- a/src/common/crypto.c +++ b/src/common/crypto.c @@ -2972,6 +2972,7 @@ secret_to_key(char *key_out, size_t key_out_len, const char *secret, /** * Destroy the <b>sz</b> bytes of data stored at <b>mem</b>, setting them to * the value <b>byte</b>. + * If <b>mem</b> is NULL or <b>sz</b> is zero, nothing happens. * * This function is preferable to memset, since many compilers will happily * optimize out memset() when they can convince themselves that the data being @@ -2989,6 +2990,13 @@ secret_to_key(char *key_out, size_t key_out_len, const char *secret, void memwipe(void *mem, uint8_t byte, size_t sz) { + if (mem == NULL || sz == 0) { + return; + } + + /* Data this large is likely to be an underflow. */ + tor_assert(sz < SIZE_T_CEILING); + /* Because whole-program-optimization exists, we may not be able to just * have this function call "memset". A smart compiler could inline it, then * eliminate dead memsets, and declare itself to be clever. */ |