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Extend local PLT reference check

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On x86, linker in binutils 2.26 and newer consolidates R_*_JUMP_SLOT with
R_*_GLOB_DAT relocation against the same symbol.  This patch extends
local PLT reference check to support alternate relocations.

	[BZ #18078]
	* scripts/check-localplt.awk: Support alternate relocations.
	* scripts/localplt.awk: Also check relocations in DT_RELA/DT_REL
	sections.
	* sysdeps/unix/sysv/linux/i386/localplt.data: Mark free and
	malloc entries with + REL R_386_GLOB_DAT.
	* sysdeps/x86_64/localplt.data: New file.
This commit is contained in:
H.J. Lu
2015-07-29 11:57:54 -07:00
parent febce2ac5f
commit 9637d8a253
6 changed files with 127 additions and 19 deletions
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40
scripts/check-localplt.awk
View File

@@ -3,9 +3,14 @@
# Each line is either a comment starting with # or it looks like:
# libfoo.so: function
# or
# libfoo.so: function + {RELA|REL} RELOC
# or
# libfoo.so: function ?
# The latter means that a PLT entry for function is optional in libfoo.so.
# The former means one is required.
# The first entry means that one is required.
# The second entry means that one is required and relocation may also be
# {RELA|REL} RELOC.
# The third entry means that a PLT entry for function is optional in
# libfoo.so.
# The second file argument is - and this (stdin) receives the output
# of the check-localplt program.
@@ -14,7 +19,10 @@ BEGIN { result = 0 }
FILENAME != "-" && /^#/ { next }
FILENAME != "-" {
if (NF != 2 && !(NF == 3 && $3 == "?")) {
if (NF == 5 && $3 == "+" && ($4 == "RELA" || $4 == "REL")) {
accept_type[$1 " " $2] = $4;
accept_reloc[$1 " " $2] = $5;
} else if (NF != 2 && !(NF == 3 && $3 == "?")) {
printf "%s:%d: bad data line: %s\n", FILENAME, FNR, $0 > "/dev/stderr";
result = 2;
} else {
@@ -23,7 +31,7 @@ FILENAME != "-" {
next;
}
NF != 2 {
NF != 2 && !(NF == 4 && ($3 == "RELA" || $3 == "REL")) {
print "Unexpected output from check-localplt:", $0 > "/dev/stderr";
result = 2;
next
@@ -31,7 +39,23 @@ NF != 2 {
{
key = $1 " " $2
if (key in accept) {
if ($3 == "RELA" || $3 == "REL") {
# Entries like:
# libc.so: free + RELA R_X86_64_GLOB_DAT
# may be ignored.
if (key in accept_type && accept_type[key] == $3 && accept_reloc[key] == $4) {
# Match
# libc.so: free + RELA R_X86_64_GLOB_DAT
delete accept_type[key]
}
} else if (NF == 2 && key in accept_reloc) {
# Match
# libc.so: free
# against
# libc.so: free + RELA R_X86_64_GLOB_DAT
if (key in accept_type)
delete accept_type[key]
} else if (key in accept) {
delete accept[key]
} else {
print "Extra PLT reference:", $0;
@@ -49,5 +73,11 @@ END {
}
}
for (key in accept_type) {
# It's mandatory.
print "Missing required PLT or " accept_reloc[key] " reference:", key;
result = 1;
}
exit(result);
}