From: norly Date: Mon, 27 May 2013 03:57:46 +0000 (+0100) Subject: Abstract model more - break 'make check' X-Git-Url: https://git.enpas.org/?p=centaur.git;a=commitdiff_plain;h=147edc30e5afb3fa0b17727fde972a0c1a9b275f Abstract model more - break 'make check' Sections are now sorted by file offset and sh_link dependencies between them as well as PHDR-SHDR dependencies are deduced as much as possible. The downside is that while the output should still work just fine, 'make check' fails to establish binary equivalence of input and output if the section table is reordered. Thankfully, in normal GCC binaries it is already ordered so we don't have to worry about this. Unfortunately the ELF spec is very lax in this regard so we have to draw a line ourselves. --- diff --git a/include/libelfu/modeltypes.h b/include/libelfu/modeltypes.h index c944234..c02eb34 100644 --- a/include/libelfu/modeltypes.h +++ b/include/libelfu/modeltypes.h @@ -12,6 +12,9 @@ typedef struct ElfuScn { Elf_Data data; + struct ElfuScn *link; + + CIRCLEQ_ENTRY(ElfuScn) elemPhdrToScn; CIRCLEQ_ENTRY(ElfuScn) elem; } ElfuScn; @@ -19,6 +22,8 @@ typedef struct ElfuScn { typedef struct ElfuPhdr { GElf_Phdr phdr; + CIRCLEQ_HEAD(PhdrToScnList, ElfuScn) phdrToScnList; + CIRCLEQ_ENTRY(ElfuPhdr) elem; } ElfuPhdr; diff --git a/src/elfops/check.c b/src/elfops/check.c index 8aaa7b5..daf6542 100644 --- a/src/elfops/check.c +++ b/src/elfops/check.c @@ -160,6 +160,22 @@ int elfu_eCheck(Elf *e) goto ERROR; } } + + /* Section addr/offset should match parent PHDR. + * Find parent PHDR: */ + for (j = 0; j < numPhdr; j++) { + if (PHDR_CONTAINS_SCN_IN_MEMORY(&phdrs[j], &shdrs[i])) { + if (!PHDR_CONTAINS_SCN_IN_FILE(&phdrs[j], &shdrs[i])) { + ELFU_WARN("elfu_eCheck: Memory/file offsets/sizes are not congruent for SHDR %d, PHDR %d.\n", i, j); + goto ERROR; + } + } + } + + /* sh_link members should not point to sections out of range. */ + if (shdrs[i].sh_link >= numShdr) { + ELFU_WARN("elfu_eCheck: Bogus sh_link in SHDR %d.\n", i); + } } } diff --git a/src/model/check.c b/src/model/check.c index 4fb042c..6dc0694 100644 --- a/src/model/check.c +++ b/src/model/check.c @@ -61,7 +61,7 @@ int elfu_mCheck(ElfuElf *me) sortedSecs[i] = ms; i++; } - assert(i = numSecs); + assert(i == numSecs); qsort(sortedSecs, numSecs, sizeof(*sortedSecs), cmpScnOffs); diff --git a/src/model/fromFile.c b/src/model/fromFile.c index bcdb91a..125ea77 100644 --- a/src/model/fromFile.c +++ b/src/model/fromFile.c @@ -7,6 +7,51 @@ #include +static int cmpScnOffs(const void *ms1, const void *ms2) +{ + assert(ms1); + assert(ms2); + + ElfuScn *s1 = *(ElfuScn**)ms1; + ElfuScn *s2 = *(ElfuScn**)ms2; + + assert(s1); + assert(s2); + + + if (s1->shdr.sh_offset < s2->shdr.sh_offset) { + return -1; + } else if (s1->shdr.sh_offset == s2->shdr.sh_offset) { + return 0; + } else /* if (s1->shdr.sh_offset > s2->shdr.sh_offset) */ { + return 1; + } +} + + + +static ElfuPhdr* parentPhdr(ElfuElf *me, ElfuScn *ms) +{ + ElfuPhdr *mp; + + assert(me); + assert(ms); + + CIRCLEQ_FOREACH(mp, &me->phdrList, elem) { + if (ms->shdr.sh_addr >= mp->phdr.p_vaddr + && OFFS_END(ms->shdr.sh_addr, ms->shdr.sh_size) <= OFFS_END(mp->phdr.p_vaddr, mp->phdr.p_memsz)) { + return mp; + } else if (ms->shdr.sh_offset >= mp->phdr.p_offset + && OFFS_END(ms->shdr.sh_offset, SCNFILESIZE(&ms->shdr)) <= OFFS_END(mp->phdr.p_offset, mp->phdr.p_filesz) + && OFFS_END(ms->shdr.sh_offset, ms->shdr.sh_size) <= OFFS_END(mp->phdr.p_offset, mp->phdr.p_memsz)) { + return mp; + } + } + + return NULL; +} + + static ElfuPhdr* modelFromPhdr(GElf_Phdr *phdr) { ElfuPhdr *mp; @@ -21,6 +66,8 @@ static ElfuPhdr* modelFromPhdr(GElf_Phdr *phdr) mp->phdr = *phdr; + CIRCLEQ_INIT(&mp->phdrToScnList); + return mp; } @@ -77,6 +124,8 @@ static ElfuScn* modelFromSection(Elf_Scn *scn) } } + ms->link = NULL; + return ms; @@ -95,6 +144,7 @@ ElfuElf* elfu_mFromElf(Elf *e) ElfuElf *me; size_t shstrndx; size_t i, numPhdr, numShdr; + ElfuScn **secArray = NULL; assert(e); if (elfu_eCheck(e)) { @@ -143,39 +193,73 @@ ElfuElf* elfu_mFromElf(Elf *e) /* Load sections */ assert(!elf_getshdrnum(e, &numShdr)); - for (i = 1; i < numShdr; i++) { - Elf_Scn *scn; - ElfuScn *ms; + if (numShdr > 1) { + secArray = malloc((numShdr - 1) * sizeof(*secArray)); + if (!secArray) { + ELFU_WARN("elfu_mFromElf: malloc() failed for secArray.\n"); + goto ERROR; + } - scn = elf_getscn(e, i); - assert(scn); + for (i = 1; i < numShdr; i++) { + Elf_Scn *scn; + ElfuScn *ms; - ms = modelFromSection(scn); - if (!ms) { - goto ERROR; + scn = elf_getscn(e, i); + assert(scn); + + ms = modelFromSection(scn); + if (!ms) { + goto ERROR; + } + + secArray[i-1] = ms; + + if (i == shstrndx) { + me->shstrtab = ms; + } } - CIRCLEQ_INSERT_TAIL(&me->scnList, ms, elem); - if (i == shstrndx) { - me->shstrtab = ms; + + /* Find sh_link dependencies */ + for (i = 0; i < numShdr - 1; i++) { + ElfuScn *ms = secArray[i]; + + if (ms->shdr.sh_link > 0) { + ms->link = secArray[ms->shdr.sh_link - 1]; + } } - } - /* Find sh_link dependencies */ + /* Sort sections by file offset */ + qsort(secArray, numShdr - 1, sizeof(*secArray), cmpScnOffs); + + /* Find PHDR -> Section dependencies (needs sorted sections) */ + for (i = 0; i < numShdr - 1; i++) { + ElfuScn *ms = secArray[i]; - /* Sort sections by offset */ + ElfuPhdr *parent = parentPhdr(me, ms); + if (parent) { + CIRCLEQ_INSERT_TAIL(&parent->phdrToScnList, ms, elemPhdrToScn); + } + } - /* Find PHDR -> Section dependencies */ + /* Put sections into list of all sections */ + for (i = 0; i < numShdr - 1; i++) { + CIRCLEQ_INSERT_TAIL(&me->scnList, secArray[i], elem); + } + } return me; ERROR: + if (secArray) { + free(secArray); + } if (me) { // TODO: Free data structures }