commit 57553571df2f33ec45a81fa5599873ddfc890c92 Author: Andrew Price Date: Thu Sep 6 14:28:19 2018 +0100 libgfs2: Fix pointer cast byte order issue lgfs2_field_assign() currently uses pointer casting to achieve generic integer assignment based on the width of the field, but this is broken as a uin32_t field can be assigned the value from the high bytes of the uint64_t value, for instance. To fix this, store the value into a uint64_t before casting to the narrower types. Signed-off-by: Andrew Price diff --git a/gfs2/libgfs2/meta.c b/gfs2/libgfs2/meta.c index a8289466..e0ea4912 100644 --- a/gfs2/libgfs2/meta.c +++ b/gfs2/libgfs2/meta.c @@ -940,6 +940,7 @@ int lgfs2_field_str(char *str, const size_t size, const char *blk, const struct int lgfs2_field_assign(char *blk, const struct lgfs2_metafield *field, const void *val) { char *fieldp = blk + field->offset; + uint64_t num = *(uint64_t *)val; if (field->flags & LGFS2_MFF_UUID) { memcpy(fieldp, val, 16); @@ -959,16 +960,16 @@ int lgfs2_field_assign(char *blk, const struct lgfs2_metafield *field, const voi switch(field->length) { case sizeof(uint8_t): - *fieldp = *(uint8_t *)val; + *fieldp = (uint8_t)num; return 0; case sizeof(uint16_t): - *(uint16_t *)fieldp = cpu_to_be16(*(uint16_t *)val); + *(uint16_t *)fieldp = cpu_to_be16((uint16_t)num); return 0; case sizeof(uint32_t): - *(uint32_t *)fieldp = cpu_to_be32(*(uint32_t *)val); + *(uint32_t *)fieldp = cpu_to_be32((uint32_t)num); return 0; case sizeof(uint64_t): - *(uint64_t *)fieldp = cpu_to_be64(*(uint64_t *)val); + *(uint64_t *)fieldp = cpu_to_be64((uint64_t)num); return 0; default: /* Will never happen */