firmware: qemu_fw_cfg: fix sysfs information leak
commit 1b656e9aad7f4886ed466094d1dc5ee4dd900d20 upstream.
Make sure to always NUL-terminate file names retrieved from the firmware
to avoid accessing data beyond the entry slab buffer and exposing it
through sysfs in case the firmware data is corrupt.
Fixes: 75f3e8e47f
("firmware: introduce sysfs driver for QEMU's fw_cfg device")
Cc: stable@vger.kernel.org # 4.6
Cc: Gabriel Somlo <somlo@cmu.edu>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20211201132528.30025-4-johan@kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:

committed by
Greg Kroah-Hartman

parent
358a4b054a
commit
ff9588cf15
@@ -601,7 +601,7 @@ static int fw_cfg_register_file(const struct fw_cfg_file *f)
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/* set file entry information */
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/* set file entry information */
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entry->size = be32_to_cpu(f->size);
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entry->size = be32_to_cpu(f->size);
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entry->select = be16_to_cpu(f->select);
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entry->select = be16_to_cpu(f->select);
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memcpy(entry->name, f->name, FW_CFG_MAX_FILE_PATH);
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strscpy(entry->name, f->name, FW_CFG_MAX_FILE_PATH);
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/* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */
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/* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */
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err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype,
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err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype,
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