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authorAlexey Dobriyan <adobriyan@openvz.org>2007-01-26 00:57:16 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-01-26 13:51:00 -0800
commit1fb844961818ce94e782acf6a96b92dc2303553b (patch)
treef58153e0e6a21ee41761786c632f6261c30a3b8b /fs/binfmt_elf.c
parentc20086de9319ac406f1e96ad459763c9f9965b18 (diff)
downloadconfigs-1fb844961818ce94e782acf6a96b92dc2303553b.tar.gz
[PATCH] core-dumping unreadable binaries via PT_INTERP
Proposed patch to fix #5 in http://www.isec.pl/vulnerabilities/isec-0017-binfmt_elf.txt aka http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2004-1073 To reproduce, do * grab poc at the end of advisory. * add line "eph.p_memsz = 4096;" after "eph.p_filesz = 4096;" where first "4096" is something equal to or greater than 4096. * ./poc /usr/bin/sudo && ls -l Here I get with 2.6.20-rc5: -rw------- 1 ad ad 102400 2007-01-15 19:17 core ---s--x--x 2 root root 101820 2007-01-15 19:15 /usr/bin/sudo Check for MAY_READ like binfmt_misc.c does. Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/binfmt_elf.c')
-rw-r--r--fs/binfmt_elf.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 90461f49e90..669dbe5b031 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -682,6 +682,15 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
retval = PTR_ERR(interpreter);
if (IS_ERR(interpreter))
goto out_free_interp;
+
+ /*
+ * If the binary is not readable then enforce
+ * mm->dumpable = 0 regardless of the interpreter's
+ * permissions.
+ */
+ if (file_permission(interpreter, MAY_READ) < 0)
+ bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
+
retval = kernel_read(interpreter, 0, bprm->buf,
BINPRM_BUF_SIZE);
if (retval != BINPRM_BUF_SIZE) {