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| author | Andrew Tridgell <tridge@samba.org> | 2008-08-24 13:56:59 +1000 |
|---|---|---|
| committer | Michael Adam <obnox@samba.org> | 2008-08-26 14:39:42 +0200 |
| commit | d9f61dbdc91fae6560361f98d981b1f7bea80422 (patch) | |
| tree | 6be75509fe252fdf14a309dfe311947a0bb9ed50 | |
| parent | 52c39dd55d0a3eda3e9ed9a0981f546ca7b88cff (diff) | |
| download | samba-d9f61dbdc91fae6560361f98d981b1f7bea80422.tar.gz samba-d9f61dbdc91fae6560361f98d981b1f7bea80422.tar.bz2 samba-d9f61dbdc91fae6560361f98d981b1f7bea80422.zip | |
Avoid a race condition in glibc between AIO and setresuid().
See this test: http://samba.org/~tridge/junkcode/aio_uid.c
The problem is that setresuid() tries to be clever about threads, and
tries to change the euid of any threads that are running. If a AIO read
or write completes while this is going on then the signal from the thread
where the IO completed is lost, as it gets -1/EPERM from rt_sigqueueinfo()
The simplest fix is to try to use setreuid() instead of setresuid(),
as setreuid() doesn't try to be clever. Unfortunately this also means
we must use become_root()/unbecome_root() in the aio code.
(This used to be commit 56c5a6f024875bb79b0104beb36f6b0ec1e1e9f9)
| -rw-r--r-- | source3/configure.in | 24 |
1 files changed, 13 insertions, 11 deletions
diff --git a/source3/configure.in b/source3/configure.in index 5508d9b01d..9436fed1ff 100644 --- a/source3/configure.in +++ b/source3/configure.in @@ -2627,30 +2627,32 @@ AC_CHECK_FUNCS(getpagesize) ################################################ # look for a method of setting the effective uid seteuid=no; + if test $seteuid = no; then -AC_CACHE_CHECK([for setresuid],samba_cv_USE_SETRESUID,[ +AC_CACHE_CHECK([for setreuid],samba_cv_USE_SETREUID,[ AC_TRY_RUN([ #define AUTOCONF_TEST 1 -#define USE_SETRESUID 1 +#define USE_SETREUID 1 #include "confdefs.h" #include "${srcdir-.}/lib/util_sec.c"], - samba_cv_USE_SETRESUID=yes,samba_cv_USE_SETRESUID=no,samba_cv_USE_SETRESUID=cross)]) -if test x"$samba_cv_USE_SETRESUID" = x"yes"; then - seteuid=yes;AC_DEFINE(USE_SETRESUID,1,[Whether setresuid() is available]) + samba_cv_USE_SETREUID=yes,samba_cv_USE_SETREUID=no,samba_cv_USE_SETREUID=cross)]) +if test x"$samba_cv_USE_SETREUID" = x"yes"; then + seteuid=yes;AC_DEFINE(USE_SETREUID,1,[Whether setreuid() is available]) fi fi - +# we check for setresuid second as it conflicts with AIO on Linux. +# see http://samba.org/~tridge/junkcode/aio_uid.c if test $seteuid = no; then -AC_CACHE_CHECK([for setreuid],samba_cv_USE_SETREUID,[ +AC_CACHE_CHECK([for setresuid],samba_cv_USE_SETRESUID,[ AC_TRY_RUN([ #define AUTOCONF_TEST 1 -#define USE_SETREUID 1 +#define USE_SETRESUID 1 #include "confdefs.h" #include "${srcdir-.}/lib/util_sec.c"], - samba_cv_USE_SETREUID=yes,samba_cv_USE_SETREUID=no,samba_cv_USE_SETREUID=cross)]) -if test x"$samba_cv_USE_SETREUID" = x"yes"; then - seteuid=yes;AC_DEFINE(USE_SETREUID,1,[Whether setreuid() is available]) + samba_cv_USE_SETRESUID=yes,samba_cv_USE_SETRESUID=no,samba_cv_USE_SETRESUID=cross)]) +if test x"$samba_cv_USE_SETRESUID" = x"yes"; then + seteuid=yes;AC_DEFINE(USE_SETRESUID,1,[Whether setresuid() is available]) fi fi |