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| author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2017-10-23 16:46:00 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-11-02 09:36:48 +0100 |
| commit | 9c73743447f244eb0e7422a285dc907283d3630e (patch) | |
| tree | 4d6692eabc7ab6cf2966a1b464b533f33812133a | |
| parent | b7be20b0175f4d148a06224df0324b5810aadb99 (diff) | |
Input: gtco - fix potential out-of-bound access
commit a50829479f58416a013a4ccca791336af3c584c7 upstream.
parse_hid_report_descriptor() has a while (i < length) loop, which
only guarantees that there's at least 1 byte in the buffer, but the
loop body can read multiple bytes which causes out-of-bounds access.
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/input/tablet/gtco.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/drivers/input/tablet/gtco.c b/drivers/input/tablet/gtco.c index a51de543a0b2..fe1ab5067b5d 100644 --- a/drivers/input/tablet/gtco.c +++ b/drivers/input/tablet/gtco.c @@ -231,13 +231,17 @@ static void parse_hid_report_descriptor(struct gtco *device, char * report, /* Walk this report and pull out the info we need */ while (i < length) { - prefix = report[i]; - - /* Skip over prefix */ - i++; + prefix = report[i++]; /* Determine data size and save the data in the proper variable */ - size = PREF_SIZE(prefix); + size = (1U << PREF_SIZE(prefix)) >> 1; + if (i + size > length) { + dev_err(ddev, + "Not enough data (need %d, have %d)\n", + i + size, length); + break; + } + switch (size) { case 1: data = report[i]; @@ -245,8 +249,7 @@ static void parse_hid_report_descriptor(struct gtco *device, char * report, case 2: data16 = get_unaligned_le16(&report[i]); break; - case 3: - size = 4; + case 4: data32 = get_unaligned_le32(&report[i]); break; } |