Matthew Wilcox reported that there is a missing mmap_lock in file_files_note that could possibly lead to a user after free. Solve this by using the existing vma snapshot for consistency and to avoid the need to take the mmap_lock anywhere in the coredump code except for dump_vma_snapshot. Update the dump_vma_snapshot to capture vm_pgoff and vm_file that are neeeded by fill_files_note. Add free_vma_snapshot to free the captured values of vm_file. Reported-by: Matthew Wilcox <willy@infradead.org> Link: https://lkml.kernel.org/r/20220131153740.2396974-1-willy@infradead.org Cc: stable@vger.kernel.org Fixes:a07279c9a8
("binfmt_elf, binfmt_elf_fdpic: use a VMA list snapshot") Fixes:2aa362c49c
("coredump: extend core dump note section to contain file names of mapped files") Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
55 lines
1.4 KiB
C
55 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_COREDUMP_H
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#define _LINUX_COREDUMP_H
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <asm/siginfo.h>
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#ifdef CONFIG_COREDUMP
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struct core_vma_metadata {
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unsigned long start, end;
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unsigned long flags;
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unsigned long dump_size;
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unsigned long pgoff;
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struct file *file;
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};
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struct coredump_params {
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const kernel_siginfo_t *siginfo;
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struct pt_regs *regs;
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struct file *file;
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unsigned long limit;
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unsigned long mm_flags;
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loff_t written;
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loff_t pos;
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loff_t to_skip;
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int vma_count;
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size_t vma_data_size;
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struct core_vma_metadata *vma_meta;
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};
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/*
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* These are the only things you should do on a core-file: use only these
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* functions to write out all the necessary info.
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*/
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extern void dump_skip_to(struct coredump_params *cprm, unsigned long to);
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extern void dump_skip(struct coredump_params *cprm, size_t nr);
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extern int dump_emit(struct coredump_params *cprm, const void *addr, int nr);
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extern int dump_align(struct coredump_params *cprm, int align);
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int dump_user_range(struct coredump_params *cprm, unsigned long start,
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unsigned long len);
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extern void do_coredump(const kernel_siginfo_t *siginfo);
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#else
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static inline void do_coredump(const kernel_siginfo_t *siginfo) {}
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#endif
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#if defined(CONFIG_COREDUMP) && defined(CONFIG_SYSCTL)
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extern void validate_coredump_safety(void);
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#else
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static inline void validate_coredump_safety(void) {}
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#endif
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#endif /* _LINUX_COREDUMP_H */
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