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| author | Paul Graham <development@winomega.com> | 2017-02-15 23:04:04 +0100 |
|---|---|---|
| committer | Paul Graham <development@winomega.com> | 2017-02-15 23:04:04 +0100 |
| commit | b2b47a7d113c2ac0e574ea4c3528780c30ef1aab (patch) | |
| tree | d4b2c836de7a47a49fe539e2cd99966a0a6bd58b /README.windows | |
| parent | 9d75e5ea975fc6d1b8b6eb333416d76144f7d2ee (diff) | |
| download | portable-b2b47a7d113c2ac0e574ea4c3528780c30ef1aab.tar.gz portable-b2b47a7d113c2ac0e574ea4c3528780c30ef1aab.tar.bz2 portable-b2b47a7d113c2ac0e574ea4c3528780c30ef1aab.zip | |
Document 32-bit time_t problem on minw-w64 toolchain and how to avoid it
Diffstat (limited to 'README.windows')
| -rw-r--r-- | README.windows | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/README.windows b/README.windows index 27c2182..a88ddc9 100644 --- a/README.windows +++ b/README.windows | |||
| @@ -12,7 +12,8 @@ cross compilers on Windows. | |||
| 12 | To configure and build LibreSSL for a 32-bit system, use the following | 12 | To configure and build LibreSSL for a 32-bit system, use the following |
| 13 | build steps: | 13 | build steps: |
| 14 | 14 | ||
| 15 | CC=i686-w64-mingw32-gcc ./configure --host=i686-w64-mingw32 | 15 | CC=i686-w64-mingw32-gcc CPPFLAGS=-D__MINGW_USE_VC2005_COMPAT \ |
| 16 | ./configure --host=i686-w64-mingw32 | ||
| 16 | make | 17 | make |
| 17 | make check | 18 | make check |
| 18 | 19 | ||
| @@ -22,6 +23,25 @@ For 64-bit builds, use these instead: | |||
| 22 | make | 23 | make |
| 23 | make check | 24 | make check |
| 24 | 25 | ||
| 26 | # Why the -D__MINGW_USE_VC2005_COMPAT flag on 32-bit systems? | ||
| 27 | |||
| 28 | An ABI change introduced with Microsoft Visual C++ 2005 (also known as | ||
| 29 | Visual C++ 8.0) switched time_t from 32-bit to 64-bit. It is important to | ||
| 30 | build LibreSSL with 64-bit time_t whenever possible, because 32-bit time_t | ||
| 31 | is unable to represent times past 2038 (this is commonly known as the | ||
| 32 | Y2K38 problem). | ||
| 33 | |||
| 34 | If LibreSSL is built with 32-bit time_t, when verifying a certificate whose | ||
| 35 | expiry date is set past 19 January 2038, it will be unable to tell if the | ||
| 36 | certificate has expired or not, and thus take the safe stance and reject it. | ||
| 37 | |||
| 38 | In order to avoid this, you need to build LibreSSL (and everything that links | ||
| 39 | with it) with the -D__MINGW_USE_VC2005_COMPAT flag. This tells mingw-w64 to | ||
| 40 | use the new ABI. | ||
| 41 | |||
| 42 | 64-bit systems always have a 64-bit time_t and are not affected by this | ||
| 43 | problem. | ||
| 44 | |||
| 25 | # Using Libressl with Visual Studio | 45 | # Using Libressl with Visual Studio |
| 26 | 46 | ||
| 27 | A script for generating ready-to-use .DLL and static .LIB files is included in | 47 | A script for generating ready-to-use .DLL and static .LIB files is included in |