From fa4751f454e6b51ef93babfd8b6c8b43a65c9db2 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Tue, 5 May 2020 12:12:54 +0200 Subject: binfmt_elf: remove the set_fs in fill_siginfo_note The code in binfmt_elf.c is differnt from the rest of the code that processes siginfo, as it sends siginfo from a kernel buffer to a file rather than from kernel memory to userspace buffers. To remove it's use of set_fs the code needs some different siginfo helpers. Add the helper copy_siginfo_to_external to copy from the kernel's internal siginfo layout to a buffer in the siginfo layout that userspace expects. Modify fill_siginfo_note to use copy_siginfo_to_external instead of set_fs and copy_siginfo_to_user. Update compat_binfmt_elf.c to use the previously added copy_siginfo_to_external32 to handle the compat case. Signed-off-by: "Eric W. Biederman" Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro --- fs/binfmt_elf.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'fs/binfmt_elf.c') diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 13f25e241ac4..a1f57e20c3cf 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1556,10 +1556,7 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm) static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata, const kernel_siginfo_t *siginfo) { - mm_segment_t old_fs = get_fs(); - set_fs(KERNEL_DS); - copy_siginfo_to_user((user_siginfo_t __user *) csigdata, siginfo); - set_fs(old_fs); + copy_siginfo_to_external(csigdata, siginfo); fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata); } -- cgit v1.2.3 From d2530b436f114dfbd1adc70c59d8d31038318726 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 5 May 2020 12:12:55 +0200 Subject: binfmt_elf: remove the set_fs(KERNEL_DS) in elf_core_dump There is no logic in elf_core_dump itself or in the various arch helpers called from it which use uaccess routines on kernel pointers except for the file writes thate are nicely encapsulated by using __kernel_write in dump_emit. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro --- fs/binfmt_elf.c | 16 +--------------- 1 file changed, 1 insertion(+), 15 deletions(-) (limited to 'fs/binfmt_elf.c') diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index a1f57e20c3cf..ba6f87ba029a 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1355,7 +1355,6 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma, vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) { u32 __user *header = (u32 __user *) vma->vm_start; u32 word; - mm_segment_t fs = get_fs(); /* * Doing it this way gets the constant folded by GCC. */ @@ -1368,14 +1367,8 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma, magic.elfmag[EI_MAG1] = ELFMAG1; magic.elfmag[EI_MAG2] = ELFMAG2; magic.elfmag[EI_MAG3] = ELFMAG3; - /* - * Switch to the user "segment" for get_user(), - * then put back what elf_core_dump() had in place. - */ - set_fs(USER_DS); if (unlikely(get_user(word, header))) word = 0; - set_fs(fs); if (word == magic.cmp) return PAGE_SIZE; } @@ -2183,7 +2176,6 @@ static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum, static int elf_core_dump(struct coredump_params *cprm) { int has_dumped = 0; - mm_segment_t fs; int segs, i; size_t vma_data_size = 0; struct vm_area_struct *vma, *gate_vma; @@ -2232,13 +2224,10 @@ static int elf_core_dump(struct coredump_params *cprm) * notes. This also sets up the file header. */ if (!fill_note_info(&elf, e_phnum, &info, cprm->siginfo, cprm->regs)) - goto cleanup; + goto end_coredump; has_dumped = 1; - fs = get_fs(); - set_fs(KERNEL_DS); - offset += sizeof(elf); /* Elf header */ offset += segs * sizeof(struct elf_phdr); /* Program headers */ @@ -2366,9 +2355,6 @@ static int elf_core_dump(struct coredump_params *cprm) } end_coredump: - set_fs(fs); - -cleanup: free_note_info(&info); kfree(shdr4extnum); kvfree(vma_filesz); -- cgit v1.2.3