The code which handles the ipl report is searching for a free location in memory where it could copy the component and certificate entries to. It checks for intersection between the sections required for the kernel and the component/certificate data area, but fails to check whether the data structures linking these data areas together intersect.
This might cause the iplreport copy code to overwrite the iplreport itself. Fix this by adding two addtional intersection checks.
Cc: stable@vger.kernel.org Fixes: 9641b8cc733f ("s390/ipl: read IPL report at early boot") Signed-off-by: Sven Schnelle svens@linux.ibm.com Reviewed-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com (cherry picked from commit a52e5cdbe8016d4e3e6322fd93d71afddb9a5af9) Signed-off-by: Sven Schnelle svens@linux.ibm.com --- arch/s390/boot/ipl_report.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/arch/s390/boot/ipl_report.c b/arch/s390/boot/ipl_report.c index 0b4965573656..88bacf4999c4 100644 --- a/arch/s390/boot/ipl_report.c +++ b/arch/s390/boot/ipl_report.c @@ -57,11 +57,19 @@ static unsigned long find_bootdata_space(struct ipl_rb_components *comps, if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && INITRD_START && INITRD_SIZE && intersects(INITRD_START, INITRD_SIZE, safe_addr, size)) safe_addr = INITRD_START + INITRD_SIZE; + if (intersects(safe_addr, size, (unsigned long)comps, comps->len)) { + safe_addr = (unsigned long)comps + comps->len; + goto repeat; + } for_each_rb_entry(comp, comps) if (intersects(safe_addr, size, comp->addr, comp->len)) { safe_addr = comp->addr + comp->len; goto repeat; } + if (intersects(safe_addr, size, (unsigned long)certs, certs->len)) { + safe_addr = (unsigned long)certs + certs->len; + goto repeat; + } for_each_rb_entry(cert, certs) if (intersects(safe_addr, size, cert->addr, cert->len)) { safe_addr = cert->addr + cert->len;