From 2d3fefd7ce64ac1015701c96916fffacc073a877 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Tue, 18 Jun 2019 14:09:09 -0300 Subject: [PATCH] posix: Fix large mmap64 offset for mips64n32 (BZ#24699) The fix for BZ#21270 (commit 158d5fa0e19) added a mask to avoid offset larger than 1^44 to be used along __NR_mmap2. However mips64n32 users __NR_mmap, as mips64n64, but still defines off_t as old non-LFS type (other ILP32, such x32, defines off_t being equal to off64_t). This leads to use the same mask meant only for __NR_mmap2 call for __NR_mmap, thus limiting the maximum offset it can use with mmap64. This patch fixes by setting the high mask only for __NR_mmap2 usage. The posix/tst-mmap-offset.c already tests it and also fails for mips64n32. The patch also change the test to check for an arch-specific header that defines the maximum supported offset. Checked on x86_64-linux-gnu, i686-linux-gnu, and I also tests tst-mmap-offset on qemu simulated mips64 with kernel 3.2.0 kernel for both mips-linux-gnu and mips64-n32-linux-gnu. [BZ #24699] * posix/tst-mmap-offset.c: Mention BZ #24699. (do_test_bz21270): Rename to do_test_large_offset and use mmap64_maximum_offset to check for maximum expected offset value. * sysdeps/generic/mmap_info.h: New file. * sysdeps/unix/sysv/linux/mips/mmap_info.h: Likewise. * sysdeps/unix/sysv/linux/mmap64.c (MMAP_OFF_HIGH_MASK): Define iff __NR_mmap2 is used. (cherry picked from commit a008c76b56e4f958cf5a0d6f67d29fade89421b7) --- ChangeLog | 11 +++++++++++ posix/tst-mmap-offset.c | 9 +++++---- sysdeps/generic/mmap_info.h | 16 ++++++++++++++++ sysdeps/unix/sysv/linux/mips/mmap_info.h | 13 +++++++++++++ sysdeps/unix/sysv/linux/mmap64.c | 9 ++++++++- 5 files changed, 53 insertions(+), 5 deletions(-) create mode 100644 sysdeps/generic/mmap_info.h create mode 100644 sysdeps/unix/sysv/linux/mips/mmap_info.h diff --git a/ChangeLog b/ChangeLog index f447559758..026f1d6b9e 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,14 @@ +2019-07-15 Adhemerval Zanella + + [BZ #24699] + * posix/tst-mmap-offset.c: Mention BZ #24699. + (do_test_bz21270): Rename to do_test_large_offset and use + mmap64_maximum_offset to check for maximum expected offset value. + * sysdeps/generic/mmap_info.h: New file. + * sysdeps/unix/sysv/linux/mips/mmap_info.h: Likewise. + * sysdeps/unix/sysv/linux/mmap64.c (MMAP_OFF_HIGH_MASK): Define iff + __NR_mmap2 is used. + 2019-07-12 Szabolcs Nagy * sysdeps/aarch64/dl-machine.h (elf_machine_lazy_rel): Check diff --git a/posix/tst-mmap-offset.c b/posix/tst-mmap-offset.c index 676c52845f..d4e53c3e67 100644 --- a/posix/tst-mmap-offset.c +++ b/posix/tst-mmap-offset.c @@ -1,4 +1,4 @@ -/* BZ #18877 and #21270 mmap offset test. +/* BZ #18877, BZ #21270, and BZ #24699 mmap offset test. Copyright (C) 2015-2019 Free Software Foundation, Inc. This file is part of the GNU C Library. @@ -24,6 +24,7 @@ #include #include #include +#include #include @@ -76,7 +77,7 @@ do_test_bz18877 (void) /* Check if invalid offset are handled correctly by mmap. */ static int -do_test_bz21270 (void) +do_test_large_offset (void) { /* For architectures with sizeof (off_t) < sizeof (off64_t) mmap is implemented with __SYS_mmap2 syscall and the offset is represented in @@ -90,7 +91,7 @@ do_test_bz21270 (void) const size_t length = 4096; void *addr = mmap64 (NULL, length, prot, flags, fd, offset); - if (sizeof (off_t) < sizeof (off64_t)) + if (mmap64_maximum_offset (page_shift) < UINT64_MAX) { if ((addr != MAP_FAILED) && (errno != EINVAL)) FAIL_RET ("mmap succeed"); @@ -110,7 +111,7 @@ do_test (void) int ret = 0; ret += do_test_bz18877 (); - ret += do_test_bz21270 (); + ret += do_test_large_offset (); return ret; } diff --git a/sysdeps/generic/mmap_info.h b/sysdeps/generic/mmap_info.h new file mode 100644 index 0000000000..b3087df2d3 --- /dev/null +++ b/sysdeps/generic/mmap_info.h @@ -0,0 +1,16 @@ +/* As default architectures with sizeof (off_t) < sizeof (off64_t) the mmap is + implemented with __SYS_mmap2 syscall and the offset is represented in + multiples of page size. For offset larger than + '1 << (page_shift + 8 * sizeof (off_t))' (that is, 1<<44 on system with + page size of 4096 bytes) the system call silently truncates the offset. + For this case, glibc mmap implementation returns EINVAL. */ + +/* Return the maximum value expected as offset argument in mmap64 call. */ +static inline uint64_t +mmap64_maximum_offset (long int page_shift) +{ + if (sizeof (off_t) < sizeof (off64_t)) + return (UINT64_C(1) << (page_shift + (8 * sizeof (off_t)))) - 1; + else + return UINT64_MAX; +} diff --git a/sysdeps/unix/sysv/linux/mips/mmap_info.h b/sysdeps/unix/sysv/linux/mips/mmap_info.h new file mode 100644 index 0000000000..07c9e3a044 --- /dev/null +++ b/sysdeps/unix/sysv/linux/mips/mmap_info.h @@ -0,0 +1,13 @@ +/* mips64n32 uses __NR_mmap for mmap64 while still having sizeof (off_t) + smaller than sizeof (off64_t). So it allows mapping large offsets + using mmap64 than 32-bit archs which uses __NR_mmap2. */ + +static inline uint64_t +mmap64_maximum_offset (long int page_shift) +{ +#if _MIPS_SIM == _ABIN32 || _MIPS_SIM == _ABI64 + return UINT64_MAX; +#else + return (UINT64_C(1) << (page_shift + (8 * sizeof (off_t)))) - 1; +#endif +} diff --git a/sysdeps/unix/sysv/linux/mmap64.c b/sysdeps/unix/sysv/linux/mmap64.c index cb56540119..671db2b654 100644 --- a/sysdeps/unix/sysv/linux/mmap64.c +++ b/sysdeps/unix/sysv/linux/mmap64.c @@ -23,11 +23,18 @@ #include #include +#ifdef __NR_mmap2 /* To avoid silent truncation of offset when using mmap2, do not accept offset larger than 1 << (page_shift + off_t bits). For archictures with 32 bits off_t and page size of 4096 it would be 1^44. */ -#define MMAP_OFF_HIGH_MASK \ +# define MMAP_OFF_HIGH_MASK \ ((-(MMAP2_PAGE_UNIT << 1) << (8 * sizeof (off_t) - 1))) +#else +/* Some ABIs might use __NR_mmap while having sizeof (off_t) smaller than + sizeof (off64_t) (currently only MIPS64n32). For this case just set + zero the higher bits so mmap with large offset does not fail. */ +# define MMAP_OFF_HIGH_MASK 0x0 +#endif #define MMAP_OFF_MASK (MMAP_OFF_HIGH_MASK | MMAP_OFF_LOW_MASK)