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nvmem: core: Fix unintentional sign extension issue

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The shifting of the u8 integer buf[3] by 24 bits to the left will
be promoted to a 32 bit signed int and then sign-extended to a
u64. In the event that the top bit of buf[3] is set then all
then all the upper 32 bits of the u64 end up as also being set
because of the sign-extension. Fix this by casting buf[i] to
a u64 before the shift.

Fixes: a28e824fb8 ("nvmem: core: Add functions to make number reading easy")
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Addresses-Coverity: ("Unintended sign extension")
Link: https://lore.kernel.org/r/20210330111241.19401-8-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Colin Ian King 2021-03-30 12:12:38 +01:00 committed by Greg Kroah-Hartman
parent a28e824fb8
commit 55022fdeac
1 changed files with 1 additions and 1 deletions
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2
drivers/nvmem/core.c
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@ -1693,7 +1693,7 @@ int nvmem_cell_read_variable_le_u64(struct device *dev, const char *cell_id,
/* Copy w/ implicit endian conversion */
*val = 0;
for (i = 0; i < len; i++)
*val |= buf[i] << (8 * i);
*val |= (uint64_t)buf[i] << (8 * i);
kfree(buf);