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authorRoland Dreier <rdreier@cisco.com>2008-10-28 16:52:20 -0700
committerJeff Garzik <jgarzik@redhat.com>2008-10-31 01:42:59 -0400
commitba14a9c291aa867896a90b3571fcc1c3759942ff (patch)
treede8e4e3023755848154b6de9e4779e166d70bfc8
parent5b97fbd093ac2e0da0c7eec894fee065a04af55d (diff)
libata: Avoid overflow in ata_tf_to_lba48() when tf->hba_lbal > 127
In ata_tf_to_lba48(), when evaluating (tf->hob_lbal & 0xff) << 24 the expression is promoted to signed int (since int can hold all values of u8). However, if hob_lbal is 128 or more, then it is treated as a negative signed value and sign-extended when promoted to u64 to | into sectors, which leads to the MSB 32 bits of section getting set incorrectly. For example, Phillip O'Donnell <phillip.odonnell@gmail.com> reported that a 1.5GB drive caused: ata3.00: HPA detected: current 2930277168, native 18446744072344861488 where 2930277168 == 0xAEA87B30 and 18446744072344861488 == 0xffffffffaea87b30 which shows the problem when hob_lbal is 0xae. Fix this by adding a cast to u64, just as is used by for hob_lbah and hob_lbam in the function. Reported-by: Phillip O'Donnell <phillip.odonnell@gmail.com> Signed-off-by: Roland Dreier <rolandd@cisco.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
-rw-r--r--drivers/ata/libata-core.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index e398df12fd1..8824c8da3f2 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1268,7 +1268,7 @@ u64 ata_tf_to_lba48(const struct ata_taskfile *tf)
sectors |= ((u64)(tf->hob_lbah & 0xff)) << 40;
sectors |= ((u64)(tf->hob_lbam & 0xff)) << 32;
- sectors |= (tf->hob_lbal & 0xff) << 24;
+ sectors |= ((u64)(tf->hob_lbal & 0xff)) << 24;
sectors |= (tf->lbah & 0xff) << 16;
sectors |= (tf->lbam & 0xff) << 8;
sectors |= (tf->lbal & 0xff);