Signed-off-by: Mark Wielaard <[email protected]> --- libdwfl/ChangeLog | 5 +++++ libdwfl/elf-from-memory.c | 57 ++++++++++++++++++++++++++++++++--------------- 2 files changed, 44 insertions(+), 18 deletions(-)
diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog index ef03973..080825e 100644 --- a/libdwfl/ChangeLog +++ b/libdwfl/ChangeLog @@ -1,5 +1,10 @@ 2015-05-19 Mark Wielaard <[email protected]> + * elf-from-memory.c (elf_from_remote_memory): Don't allocate all + phdrs on the stack. Allocate with malloc and free when done. + +2015-05-19 Mark Wielaard <[email protected]> + * linux-kernel-modules.c (dwfl_linux_kernel_find_elf): malloc and free alternate_name. diff --git a/libdwfl/elf-from-memory.c b/libdwfl/elf-from-memory.c index b35fac7..5595d96 100644 --- a/libdwfl/elf-from-memory.c +++ b/libdwfl/elf-from-memory.c @@ -1,5 +1,5 @@ /* Reconstruct an ELF file by reading the segments out of remote memory. - Copyright (C) 2005-2011, 2014 Red Hat, Inc. + Copyright (C) 2005-2011, 2014, 2015 Red Hat, Inc. This file is part of elfutils. This file is free software; you can redistribute it and/or modify @@ -63,6 +63,10 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, size_t maxread), void *arg) { + /* We might have to reserve some memory for the phdrs. Set to NULL + here so we can always safely free it. */ + void *phdrsp = NULL; + /* First read in the file header and check its sanity. */ const size_t initial_bufsize = 256; @@ -80,6 +84,7 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, { read_error: free (buffer); + free (phdrsp); __libdwfl_seterrno (nread < 0 ? DWFL_E_ERRNO : DWFL_E_TRUNCATED); return NULL; } @@ -88,6 +93,7 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, { bad_elf: free (buffer); + free (phdrsp); __libdwfl_seterrno (DWFL_E_BADELF); return NULL; } @@ -172,6 +178,7 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, if (newbuf == NULL) { free (buffer); + free (phdrsp); goto no_memory; } buffer = newbuf; @@ -184,14 +191,22 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, xlatefrom.d_buf = buffer; } - union + typedef union { Elf32_Phdr p32[phnum]; Elf64_Phdr p64[phnum]; - } phdrs; + } phdrsn; - xlateto.d_buf = &phdrs; - xlateto.d_size = sizeof phdrs; + phdrsp = malloc (sizeof (phdrsn)); + if (phdrsp == NULL) + { + free (buffer); + goto no_memory; + } + phdrsn *phdrs = (phdrsn *) phdrsp; + + xlateto.d_buf = phdrs; + xlateto.d_size = sizeof (phdrsn); /* Scan for PT_LOAD segments to find the total size of the file image. */ size_t contents_size = 0; @@ -234,9 +249,9 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, ehdr.e32.e_ident[EI_DATA]) == NULL) goto libelf_error; for (uint_fast16_t i = 0; i < phnum; ++i) - if (phdrs.p32[i].p_type == PT_LOAD) - if (handle_segment (phdrs.p32[i].p_vaddr, phdrs.p32[i].p_offset, - phdrs.p32[i].p_filesz, phdrs.p32[i].p_memsz)) + if (phdrs->p32[i].p_type == PT_LOAD) + if (handle_segment (phdrs->p32[i].p_vaddr, phdrs->p32[i].p_offset, + phdrs->p32[i].p_filesz, phdrs->p32[i].p_memsz)) goto bad_elf; break; @@ -245,9 +260,9 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, ehdr.e64.e_ident[EI_DATA]) == NULL) goto libelf_error; for (uint_fast16_t i = 0; i < phnum; ++i) - if (phdrs.p64[i].p_type == PT_LOAD) - if (handle_segment (phdrs.p64[i].p_vaddr, phdrs.p64[i].p_offset, - phdrs.p64[i].p_filesz, phdrs.p64[i].p_memsz)) + if (phdrs->p64[i].p_type == PT_LOAD) + if (handle_segment (phdrs->p64[i].p_vaddr, phdrs->p64[i].p_offset, + phdrs->p64[i].p_filesz, phdrs->p64[i].p_memsz)) goto bad_elf; break; @@ -276,7 +291,10 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, /* Now we know the size of the whole image we want read in. */ buffer = calloc (1, contents_size); if (buffer == NULL) - goto no_memory; + { + free (phdrsp); + goto no_memory; + } switch (ehdr.e32.e_ident[EI_CLASS]) { @@ -297,9 +315,9 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, case ELFCLASS32: for (uint_fast16_t i = 0; i < phnum; ++i) - if (phdrs.p32[i].p_type == PT_LOAD) - if (handle_segment (phdrs.p32[i].p_vaddr, phdrs.p32[i].p_offset, - phdrs.p32[i].p_filesz)) + if (phdrs->p32[i].p_type == PT_LOAD) + if (handle_segment (phdrs->p32[i].p_vaddr, phdrs->p32[i].p_offset, + phdrs->p32[i].p_filesz)) goto read_error; /* If the segments visible in memory didn't include the section @@ -324,9 +342,9 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, case ELFCLASS64: for (uint_fast16_t i = 0; i < phnum; ++i) - if (phdrs.p64[i].p_type == PT_LOAD) - if (handle_segment (phdrs.p64[i].p_vaddr, phdrs.p64[i].p_offset, - phdrs.p64[i].p_filesz)) + if (phdrs->p64[i].p_type == PT_LOAD) + if (handle_segment (phdrs->p64[i].p_vaddr, phdrs->p64[i].p_offset, + phdrs->p64[i].p_filesz)) goto read_error; /* If the segments visible in memory didn't include the section @@ -354,6 +372,9 @@ elf_from_remote_memory (GElf_Addr ehdr_vma, break; } + free (phdrsp); + phdrs = phdrsp = NULL; + /* Now we have the image. Open libelf on it. */ Elf *elf = elf_memory ((char *) buffer, contents_size); -- 1.8.3.1
