Skip to content

Move section headers if they would be overwritten #39

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Jul 23, 2015
Merged

Move section headers if they would be overwritten #39

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
21 changes: 16 additions & 5 deletions src/patchelf.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -711,11 +711,22 @@ void ElfFile<ElfFileParamNames>::rewriteSectionsExecutable()
Elf_Addr firstPage = startAddr - startOffset;
debug("first page is 0x%llx\n", (unsigned long long) firstPage);

/* Right now we assume that the section headers are somewhere near
the end, which appears to be the case most of the time.
Therefore they're not accidentally overwritten by the replaced
sections. !!! Fix this. */
assert((off_t) rdi(hdr->e_shoff) >= startOffset);
if ((off_t) rdi(hdr->e_shoff) < startOffset) {
/* The section headers occur too early in the file and would be
overwritten by the replaced sections. Move them to the end of the file
before proceeding. */
off_t shoffNew = fileSize;
off_t shSize = rdi(hdr->e_shoff) + rdi(hdr->e_shnum) * rdi(hdr->e_shentsize);
growFile (fileSize + shSize);
wri(hdr->e_shoff, shoffNew);

/* Rewrite the section header table. For neatness, keep the
sections sorted. */
assert(rdi(hdr->e_shnum) == shdrs.size());
sortShdrs();
for (unsigned int i = 1; i < rdi(hdr->e_shnum); ++i)
* ((Elf_Shdr *) (contents + rdi(hdr->e_shoff)) + i) = shdrs[i];
}


/* Compute the total space needed for the replaced sections, the
Expand Down