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93 lines
3.0 KiB
93 lines
3.0 KiB
From 1e48901166efd65c574de9f6a2b7139721b72623 Mon Sep 17 00:00:00 2001 |
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From: Yauheni Kaliuta <yauheni.kaliuta@redhat.com> |
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Date: Wed, 19 Jul 2017 17:56:49 +0300 |
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Subject: [PATCH] libkmod-elf: resolve CRC if module is built with |
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MODULE_REL_CRCS |
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Normally exported symbol's crc is stored as absolute (SHN_ABS) |
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value of special named symbol __crc_<symbol name>. |
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When the kernel and modules are built with the config option |
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CONFIG_MODULE_REL_CRCS, all the CRCs are put in a special section |
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and the __crc_<symbol name> symbols values are offsets in the |
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section. See patch description of the commit: |
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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=56067812d5b0e737ac2063e94a50f76b810d6ca3 |
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Add kmod support of this configuration. |
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Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com> |
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--- |
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libkmod/libkmod-elf.c | 30 +++++++++++++++++++++++++++++- |
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1 file changed, 29 insertions(+), 1 deletion(-) |
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diff --git a/libkmod/libkmod-elf.c b/libkmod/libkmod-elf.c |
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index 90da89aebbaf..ef4a8a3142a1 100644 |
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--- a/libkmod/libkmod-elf.c |
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+++ b/libkmod/libkmod-elf.c |
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@@ -747,6 +747,31 @@ static inline uint8_t kmod_symbol_bind_from_elf(uint8_t elf_value) |
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} |
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} |
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+static uint64_t kmod_elf_resolve_crc(const struct kmod_elf *elf, uint64_t crc, uint16_t shndx) |
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+{ |
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+ int err; |
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+ uint64_t off, size; |
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+ uint32_t nameoff; |
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+ |
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+ if (shndx == SHN_ABS || shndx == SHN_UNDEF) |
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+ return crc; |
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+ |
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+ err = elf_get_section_info(elf, shndx, &off, &size, &nameoff); |
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+ if (err < 0) { |
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+ ELFDBG("Cound not find section index %"PRIu16" for crc", shndx); |
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+ return (uint64_t)-1; |
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+ } |
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+ |
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+ if (crc > (size - sizeof(uint32_t))) { |
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+ ELFDBG("CRC offset %"PRIu64" is too big, section %"PRIu16" size is %"PRIu64"\n", |
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+ crc, shndx, size); |
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+ return (uint64_t)-1; |
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+ } |
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+ |
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+ crc = elf_get_uint(elf, off + crc, sizeof(uint32_t)); |
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+ return crc; |
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+} |
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+ |
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/* array will be allocated with strings in a single malloc, just free *array */ |
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int kmod_elf_get_symbols(const struct kmod_elf *elf, struct kmod_modversion **array) |
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{ |
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@@ -830,6 +855,7 @@ int kmod_elf_get_symbols(const struct kmod_elf *elf, struct kmod_modversion **ar |
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uint32_t name_off; |
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uint64_t crc; |
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uint8_t info, bind; |
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+ uint16_t shndx; |
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#define READV(field) \ |
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elf_get_uint(elf, sym_off + offsetof(typeof(*s), field),\ |
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@@ -839,11 +865,13 @@ int kmod_elf_get_symbols(const struct kmod_elf *elf, struct kmod_modversion **ar |
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name_off = READV(st_name); |
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crc = READV(st_value); |
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info = READV(st_info); |
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+ shndx = READV(st_shndx); |
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} else { |
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Elf64_Sym *s; |
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name_off = READV(st_name); |
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crc = READV(st_value); |
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info = READV(st_info); |
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+ shndx = READV(st_shndx); |
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} |
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#undef READV |
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name = elf_get_mem(elf, str_off + name_off); |
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@@ -856,7 +884,7 @@ int kmod_elf_get_symbols(const struct kmod_elf *elf, struct kmod_modversion **ar |
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else |
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bind = ELF64_ST_BIND(info); |
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- a[count].crc = crc; |
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+ a[count].crc = kmod_elf_resolve_crc(elf, crc, shndx); |
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a[count].bind = kmod_symbol_bind_from_elf(bind); |
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a[count].symbol = itr; |
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slen = strlen(name); |
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-- |
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2.14.0.rc0 |
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