Messages in this thread Patch in this message | | | Date | Tue, 7 Aug 2012 22:50:56 +0200 (CEST) | From | Jesper Juhl <> | Subject | [PATCH] tpm: Do not dereference NULL pointer if acpi_os_map_memory() fails. |
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In drivers/char/tpm/tpm_bios.c::read_log() we call acpi_os_map_memory(). That call may fail for a number of reasons (invallid address, out of memory etc). If the call fails it returns NULL and we just pass that to memcpy() unconditionally, which will go bad when it tries to dereference the pointer.
Unfortunately we just get NULL back, so we can't really tell the user exactely what went wrong, but we can at least avoid crashing and return an error (-EIO seemed more generic and more suitable here than -ENOMEM or something else, so I picked that).
Signed-off-by: Jesper Juhl <jj@chaosbits.net> --- drivers/char/tpm/tpm_bios.c | 5 +++++ 1 file changed, 5 insertions(+)
Compile tested only.
diff --git a/drivers/char/tpm/tpm_bios.c b/drivers/char/tpm/tpm_bios.c index 0636520..0c5c274 100644 --- a/drivers/char/tpm/tpm_bios.c +++ b/drivers/char/tpm/tpm_bios.c @@ -410,6 +410,11 @@ static int read_log(struct tpm_bios_log *log) log->bios_event_log_end = log->bios_event_log + len; virt = acpi_os_map_memory(start, len); + if (!virt) { + printk("%s: ERROR - Unable to map memory\n", + __func__); + return -EIO; + } memcpy(log->bios_event_log, virt, len); -- 1.7.11.4
-- Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/ Don't top-post http://www.catb.org/jargon/html/T/top-post.html Plain text mails only, please.
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