4.19-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 0c5d6cb6643f48ad3775322f3ebab6c7eb67484e ]
If the application buffer was too small to fit all the names we would still count the number of bytes and return this for listxattr. This would then trigger a BUG in usercopy.c
Fix the computation of the size so that we return -ERANGE correctly when the buffer is too small.
This fixes the kernel BUG for xfstest generic/377
Signed-off-by: Ronnie Sahlberg lsahlber@redhat.com Signed-off-by: Steve French stfrench@microsoft.com Reviewed-by: Aurelien Aptel aaptel@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/cifs/smb2ops.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 89985a0a6819..812da3e56a22 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -686,6 +686,7 @@ move_smb2_ea_to_cifs(char *dst, size_t dst_size, int rc = 0; unsigned int ea_name_len = ea_name ? strlen(ea_name) : 0; char *name, *value; + size_t buf_size = dst_size; size_t name_len, value_len, user_name_len;
while (src_size > 0) { @@ -721,9 +722,10 @@ move_smb2_ea_to_cifs(char *dst, size_t dst_size, /* 'user.' plus a terminating null */ user_name_len = 5 + 1 + name_len;
- rc += user_name_len; - - if (dst_size >= user_name_len) { + if (buf_size == 0) { + /* skip copy - calc size only */ + rc += user_name_len; + } else if (dst_size >= user_name_len) { dst_size -= user_name_len; memcpy(dst, "user.", 5); dst += 5; @@ -731,8 +733,7 @@ move_smb2_ea_to_cifs(char *dst, size_t dst_size, dst += name_len; *dst = 0; ++dst; - } else if (dst_size == 0) { - /* skip copy - calc size only */ + rc += user_name_len; } else { /* stop before overrun buffer */ rc = -ERANGE;