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author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-05-06 16:13:31 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-05-06 16:13:31 -0700 |
commit | 0bc40e549aeea2de20fc571749de9bbfc099fb34 (patch) | |
tree | d18f3339bd383a17431fca23b6c5f3e54c93cf2f /arch/x86/kernel/kprobes | |
parent | e913c4a4c21cd83317fafe63bfdc9d34d2910114 (diff) | |
parent | caa841360134f863987f2d4f77b8dc2fbb7596f8 (diff) |
Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm updates from Ingo Molnar:
"The changes in here are:
- text_poke() fixes and an extensive set of executability lockdowns,
to (hopefully) eliminate the last residual circumstances under
which we are using W|X mappings even temporarily on x86 kernels.
This required a broad range of surgery in text patching facilities,
module loading, trampoline handling and other bits.
- tweak page fault messages to be more informative and more
structured.
- remove DISCONTIGMEM support on x86-32 and make SPARSEMEM the
default.
- reduce KASLR granularity on 5-level paging kernels from 512 GB to
1 GB.
- misc other changes and updates"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
x86/mm: Initialize PGD cache during mm initialization
x86/alternatives: Add comment about module removal races
x86/kprobes: Use vmalloc special flag
x86/ftrace: Use vmalloc special flag
bpf: Use vmalloc special flag
modules: Use vmalloc special flag
mm/vmalloc: Add flag for freeing of special permsissions
mm/hibernation: Make hibernation handle unmapped pages
x86/mm/cpa: Add set_direct_map_*() functions
x86/alternatives: Remove the return value of text_poke_*()
x86/jump-label: Remove support for custom text poker
x86/modules: Avoid breaking W^X while loading modules
x86/kprobes: Set instruction page as executable
x86/ftrace: Set trampoline pages as executable
x86/kgdb: Avoid redundant comparison of patched code
x86/alternatives: Use temporary mm for text poking
x86/alternatives: Initialize temporary mm for patching
fork: Provide a function for copying init_mm
uprobes: Initialize uprobes earlier
x86/mm: Save debug registers when loading a temporary mm
...
Diffstat (limited to 'arch/x86/kernel/kprobes')
-rw-r--r-- | arch/x86/kernel/kprobes/core.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 122548ad5c2e..cf52ee0d8711 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -431,8 +431,21 @@ void *alloc_insn_page(void) void *page; page = module_alloc(PAGE_SIZE); - if (page) - set_memory_ro((unsigned long)page & PAGE_MASK, 1); + if (!page) + return NULL; + + set_vm_flush_reset_perms(page); + /* + * First make the page read-only, and only then make it executable to + * prevent it from being W+X in between. + */ + set_memory_ro((unsigned long)page, 1); + + /* + * TODO: Once additional kernel code protection mechanisms are set, ensure + * that the page was not maliciously altered and it is still zeroed. + */ + set_memory_x((unsigned long)page, 1); return page; } @@ -440,8 +453,6 @@ void *alloc_insn_page(void) /* Recover page to RW mode before releasing it */ void free_insn_page(void *page) { - set_memory_nx((unsigned long)page & PAGE_MASK, 1); - set_memory_rw((unsigned long)page & PAGE_MASK, 1); module_memfree(page); } |