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envelope-from=borntraeger@linux.ibm.com; helo=mx0a-001b2d01.pphosted.com X-Spam_score_int: -26 X-Spam_score: -2.7 X-Spam_bar: -- X-Spam_report: (-2.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Joshua Daley In the dir_rem[level] == 0 case, level is decremented, then a virtio_read() is issued on sec_loc[level]. If level is -1, then the 4 bytes before the static sec_loc array are read, and the virtio_read() is issued on that garbage block number. Guard the call to virtio_read() against the value of level to prevent this. Fixes: 869648e87eeb ("pc-bios/s390-ccw: El Torito 16-bit boot image size field workaround") Signed-off-by: Joshua Daley Reviewed-by: Christian Borntraeger --- pc-bios/s390-ccw/bootmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c index 420ee32eff..ed6e8cbbc7 100644 --- a/pc-bios/s390-ccw/bootmap.c +++ b/pc-bios/s390-ccw/bootmap.c @@ -902,7 +902,7 @@ static inline long iso_get_file_size(uint32_t load_rba) if (dir_rem[level] == 0) { /* Nothing remaining */ level--; - if (virtio_read(sec_loc[level], temp)) { + if (level >= 0 && virtio_read(sec_loc[level], temp)) { puts("Failed to read ISO directory"); return -EIO; } -- 2.53.0