ACPI: APEI / ERST: Fix missing error handling in erst_reader()
BugLink: http://bugs.launchpad.net/bugs/1745069 commit bb82e0b4 upstream. The commit f6f82851 ("pstore: pass allocated memory region back to caller") changed the check of the return value from erst_read() in erst_reader() in the following way: if (len == -ENOENT) goto skip; - else if (len < 0) { - rc = -1; + else if (len < sizeof(*rcd)) { + rc = -EIO; goto out; This introduced another bug: since the comparison with sizeof() is cast to unsigned, a negative len value doesn't hit any longer. As a result, when an error is returned from erst_read(), the code falls through, and it may eventually lead to some weird thing like memory corruption. This patch adds the negative error value check more explicitly for addressing the issue. Fixes: f6f82851 (pstore: pass allocated memory region back to caller) Tested-by: Jerry Tang <jtang@suse.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Acked-by: Kees Cook <keescook@chromium.org> Reviewed-by: Borislav Petkov <bp@suse.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
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