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SubjectRe: [PATCH 08/15] binfmt_flat: add endianess annotations
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On 6/10/19 10:20 PM, Christoph Hellwig wrote:
> Most binfmt_flat on-disk fields are big endian. Use the proper __be32
> type where applicable.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/binfmt_flat.c | 26 ++++++++++++++++----------
> 1 file changed, 16 insertions(+), 10 deletions(-)

Tested-by: Vladimir Murzin <vladimir.murzin@arm.com>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>

>
> diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
> index 6ae0f9af3fc9..6c1848dee724 100644
> --- a/fs/binfmt_flat.c
> +++ b/fs/binfmt_flat.c
> @@ -421,7 +421,8 @@ static int load_flat_file(struct linux_binprm *bprm,
> unsigned long textpos, datapos, realdatastart;
> u32 text_len, data_len, bss_len, stack_len, full_data, flags;
> unsigned long len, memp, memp_size, extra, rlim;
> - u32 __user *reloc, *rp;
> + __be32 __user *reloc;
> + u32 __user *rp;
> struct inode *inode;
> int i, rev, relocs;
> loff_t fpos;
> @@ -594,7 +595,7 @@ static int load_flat_file(struct linux_binprm *bprm,
> goto err;
> }
>
> - reloc = (u32 __user *)
> + reloc = (__be32 __user *)
> (datapos + (ntohl(hdr->reloc_start) - text_len));
> memp = realdatastart;
> memp_size = len;
> @@ -619,7 +620,7 @@ static int load_flat_file(struct linux_binprm *bprm,
> MAX_SHARED_LIBS * sizeof(u32),
> FLAT_DATA_ALIGN);
>
> - reloc = (u32 __user *)
> + reloc = (__be32 __user *)
> (datapos + (ntohl(hdr->reloc_start) - text_len));
> memp = textpos;
> memp_size = len;
> @@ -785,15 +786,16 @@ static int load_flat_file(struct linux_binprm *bprm,
> u32 __maybe_unused persistent = 0;
> for (i = 0; i < relocs; i++) {
> u32 addr, relval;
> + __be32 tmp;
>
> /*
> * Get the address of the pointer to be
> * relocated (of course, the address has to be
> * relocated first).
> */
> - if (get_user(relval, reloc + i))
> + if (get_user(tmp, reloc + i))
> return -EFAULT;
> - relval = ntohl(relval);
> + relval = ntohl(tmp);
> addr = flat_get_relocate_addr(relval);
> rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1);
> if (rp == (u32 __user *)RELOC_FAILED) {
> @@ -812,8 +814,13 @@ static int load_flat_file(struct linux_binprm *bprm,
> * Do the relocation. PIC relocs in the data section are
> * already in target order
> */
> - if ((flags & FLAT_FLAG_GOTPIC) == 0)
> - addr = ntohl(addr);
> + if ((flags & FLAT_FLAG_GOTPIC) == 0) {
> + /*
> + * Meh, the same value can have a different
> + * byte order based on a flag..
> + */
> + addr = ntohl((__force __be32)addr);
> + }
> addr = calc_reloc(addr, libinfo, id, 0);
> if (addr == RELOC_FAILED) {
> ret = -ENOEXEC;
> @@ -828,11 +835,10 @@ static int load_flat_file(struct linux_binprm *bprm,
> }
> } else {
> for (i = 0; i < relocs; i++) {
> - u32 relval;
> + __be32 relval;
> if (get_user(relval, reloc + i))
> return -EFAULT;
> - relval = ntohl(relval);
> - old_reloc(relval);
> + old_reloc(ntohl(relval));
> }
> }
>
>

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